Disease surveillance. Read this interview and find out how you can help...

Disease surveillance: researcher explains how you can help

We speak to Mauricio Santillana, Boston Children’s Hospital and Harvard University, about his new paper on the use of Google searches in disease surveillance. Not only are search engines a vital tool for fighting dengue, they connect the community in a novel way, opening the door to crowd-sourced real-time outbreak monitoring.

What was already known, and what question(s) were you attempting to answer?

Multiple previous studies have explored the utility of using information from Internet searches to track disease activity in a given location. Google Flu Trends (GFT) is one of the earliest attempts aimed at tracking flu activity in the USA and other countries using flu-related Google search activity in the population. Unfortunately, GFT was shown to poorly track flu activity on multiple occasions and was discontinued in 2015. An array of studies has emerged, attempting to revisit the idea of using Internet searches to track diseases. In a recent study, our team introduced a methodology that leads to accurate tracking of flu in the USA at the national level using Internet search data.

Most of the previous research studying disease tracking with Internet search information has been conducted in developed and wealthy countries where internet penetration is high and healthcare-based disease surveillance systems have been in place for multiple decades. However, few studies have investigated the capabilities of using these novel methodologies to track neglected tropical diseases in less developed countries; similarly, the limitations of these methodologies, and how the tracking accuracy relates to the underlying characteristics of a country, such as Internet penetration and disease prevalence, are investigated by very few studies.

Read about the hidden economic cost of dengue

In this research, we studied the potential of using dengue-related Google search activity to track real-time dengue activity in five very distinct countries/states around the world: Mexico, Brazil, Thailand, Singapore, Taiwan. Specifically, we studied the capabilities and limitations of using Internet search activity to track dengue in less developed countries, as well as how the tracking accuracy relates to the underlying characteristics of a country.

What is the most important finding of your study?

By extending our methodology ARGO (AutoRegression with Google search queries), initially introduced for flu surveillance, to track dengue in these five countries/states, we show that:

(i) the lessons learned to track influenza in data-rich environments, like the United States, can be effectively used to develop methodologies to track an often-neglected tropical disease, dengue, in data-poor environments;

(ii) even in countries where traditional health care-based disease surveillance systems are lacking, properly developed methods using Internet searches of those countries can give accurate tracking of dengue;

(iii) our ARGO method significantly improves the tracking of dengue, which is particularly important for countries with less advanced clinical based disease surveillance systems, and

(iv) dengue-tracking methods based on Internet searches perform best in dengue-endemic areas with a high number of yearly cases and with sustained seasonal incidence.

What are the larger implications of your findings?

Previous inaccuracies of disease tracking systems such as Google Flu Trends and Google Dengue Trends led many public health officials to question the capabilities of big data approaches in tracking epidemic outbreaks. We show in our study that despite the discontinuation of Google Flu Trends and Google Dengue Trends, it is still meaningful to formulate, develop, and refine robust methodologies that are capable of extracting disease-related information from data sources not designed to do so.

In short, we have shown that information from Internet search engines can be used effectively to track mosquito-borne diseases with proper and rigorous statistical methods (i.e., analytics). This is particularly useful for less developed countries, where traditional clinical-based reporting systems are often delayed or missing. This alternative way of tracking disease can be used to alert governments and hospitals when elevated dengue incidence is anticipated, and provide safety information for travelers.

Based on your findings, what are the next steps for this research?

Future work should include investigating the feasibility of applying our methodology to other countries, finer spatial and temporal resolutions, as well as to other infectious diseases.

In a nutshell, what’s the most exciting aspect of the study?

The wide availability of Internet throughout the globe provides the potential for alternatives for reliably tracking dengue and other infectious diseases faster than traditional clinical-based systems. Such a development would be particularly useful for less developed countries, but proper and rigorous statistical methods are needed for the potential to be realized.

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Surge in dengue fever publications

The number of dengue fever publications has grown strongly since 1960.

According to an analysis of PubMed, performed by Break Dengue, just five search results were returned for ‘dengue fever’ in the year 1960. This rose gently until the late 1990s when the graph turned upwards. After that, growth was exponential. In 2015, more than 1,500 papers were published on dengue fever.

This reflects the strong growth in academic and public health interest in dengue fever, as well as increased research funding for this serious disease. The trend follows a growth in the number of cases of dengue worldwide – and reflects the urgent need to contain its spread.

Dengue fever publications: highlights from 2017

This year has seen several notable dengue publications on topics ranging from mosquito control and dengue treatment to disease surveillance and the burden of disease including the economic cost of dengue.

1. Lancet Infectious Diseases published a study by Castro, Wilson, and Bloom – all from Harvard – on the large and growing burden of dengue fever. The paper explores not only the number of cases but the economic impact of outbreaks.

2. A study published in BMC Infectious Diseases looked at early warning signals for dengue outbreaks in Colombia using a mix of climate and other data. Colombia faces a range of competing, health challenges. An early warning system would help decision-makers to prioritize how they use resources and getting better value for money.

3. A paper by experts in Taiwan explores the role of public transport in the spread of dengue in urban settings. The authors look at metro passenger numbers and how this relates to dengue outbreaks. They found that large flows of passengers through metro stations can dramatically increase the risk of dengue in the neighborhood.

4. The disease burden of dengue in the Philippines is the focus of a study published in the American Journal of Tropical Medicine and Hygiene. The authors aim to address the underreporting of cases in order to get a more accurate estimate of the trust burden of disease. We will have an interview feature on this topic in the coming weeks.

5. Looking ahead, an important publication is due for a release this coming summer examining the role of search engines in tracking dengue. While this paper remains under embargo, we can whet your appetite by saying that it looks at the potential of combining search engine data with official clinical information in five countries. Watch this space.

What is clear is that the commitment among academics and funding agencies to understanding dengue fever is stronger than ever. So too is the level of diversity we see in the kinds of papers being published. No longer are dengue fever publications the exclusive domain of mosquito experts and biochemists, economists and mathematical modelers have entered the fray.

The big question is whether the growth in knowledge from multiple disciplines can be translated into strategies that improve our power to break dengue.

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Double dengue: why a second dengue infection is worse than the first – and what it means for vaccination

The impact of a second dengue infection can be amplified due to antibodies produced to fight off an earlier infection. That’s why dengue vaccination may be best for those who have already recovered from the disease.

‘Antibody enhancement’ may sound like technical medical jargon but the immunological theory is having its day in the sun. It is the idea that explains why the first brush with a dengue virus is less serious than the second.

‘There are thousands of dengue cases across the world each year, making dengue viruses one of the most important mosquito-borne pathogens,’ explains Professor Pratit Samdani, a renowned dengue expert in Mumbai, India. ‘There are four types of dengue – known as DEN I, DEN II, DEN III and DEN IV – and while infection with one virus will make you seriously ill, the symptoms can become potentially fatal when infected subsequently with a different strain.’

The science behind this phenomenon is fascinating. It turns out that natural proteins called antibodies, produced by the body to fight infection, help defeat the first dengue virus but leave us susceptible if we are later hit with another dengue virus.

‘Whenever one gets an infection you get antibodies,’ says Prof Samdani. ‘In dengue, these antibodies let the second virus enter the cells easily, increasing the risk of dengue hemorrhagic fever! This is because of a phenomenon called antibody-dependent enhancement.’

This explanation is supported by most experts in the field, including Prof Tikki Pang at the University of Singapore’s Lee Kuan Yew School of Public Policy. ‘Instead of protecting the individual during a second dengue infection with a different dengue serotype, it enhances virus replication and causes more severe disease,’ he says.

Who should have the dengue vaccine?

The impact of second dengue infection has been in the news this month after Sanofi Pasteur, the company that developed the world’s first dengue vaccine, shared new data on the impact of prior dengue infection.

The company has found that the vaccine protects against disease in those who had been infected before vaccination. For those who have never been infected, vaccination may not be advisable as the body responds in the same way as it would to an initial infection. Thus, a second dengue infection could be more severe.

‘Ideally, people should do a diagnostic test first to determine if they have ever been exposed to dengue, but this is not always possible,’ says Prof Pang. ‘Instead, a good knowledge of a previous history of dengue infection and physicians’ acumen and experience are important.’

While most people in endemic areas have been infected by the time they reach adolescence, many cases are mild or ‘silent’ – which serious or lasting symptoms.

‘In endemic areas, people who have never been infected by dengue are in the minority – in most endemic countries 90% are infected by the time they reach adolescence, without necessarily becoming ill,’ says Prof Pang. ‘The vaccine is still very safe and not all of those who are facing the risk of a second infection, develop a severe form of the disease. Actually, the vast majority don’t.’

Better diagnostics and surveillance needed

The new data on how best to use the vaccine has caused confusion in some quarters. In the Philippines, for example, a pioneering immunization campaign has been put on hold and a political row is brewing.

ADVA – the Asian Dengue Vaccine Advocacy group – released a statement explaining the science and calling for calm. ‘This outcome should not cause undue panic among individuals who have already received the dengue vaccine,’ it said. ‘Seropositive individuals would benefit from receiving the vaccine.’

The group said serological pretesting would help doctors to determine whether patients were suitable candidates for the vaccine, adding that an ‘appropriate, cheap’ test should be made universally available.

The furor over the dengue vaccine has sparked concerns that vaccine uptake and development might be harmed by negative headlines.

‘Once you cut through the noise, what is most apparent is that the global dengue community – particularly in areas of high endemicity – urgently need better dengue diagnostics and disease surveillance reporting,’ said Kamran Rafiq, International Society for Neglected Tropical Diseases.

‘This news could potentially mean delays in the global vaccine development pipeline by forcing longer waits for safety issues to be cleared, underlining the pressing need to differentiate between seropositive and seronegative patients.’

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Dengue in Mumbai: ‘Now I know why it’s called breakbone fever’

Down with dengue in Mumbai

When Gayatri Rangachari Shah was bitten by a mosquito she knew she was at risk of dengue fever. Soon she began to feel weak and in pain. It wasn’t long before she was in hospital.

Residents have become accustomed to outbreaks of dengue in Mumbai. Hundreds of cases have been recorded in the Indian mega-city during the monsoon season, despite efforts to clear mosquito breeding sites.

Image of Gayatri Rangachair Shah

For Gayatri Rangachair Shah, a well-traveled journalist, the dangers of dengue have been lurking in the background since she moved to Mumbai. A contributing editor at Vogue India and Vice President, India at Women in the World, and CNN contributor, she has lived in Islamabad, Algiers, London, New Delhi, Boston and New York.

Dengue doesn’t fit into Gayatri’s hectic schedule but when she first noticed symptoms, she was already preparing for the worst. ‘I came down with a fever and body ache,’ she recalls. ‘I didn’t know for sure that I had dengue but I did recall being bitten by a mosquito and I thought perhaps it could be dengue given the widespread reporting of dengue in Mumbai, where I live.’

As time wore on, the symptoms worsened. How did it feel when she was in the grip of dengue fever? ‘Ugh. In a word, wretched. Ghastly and draining,’ Gayatri says. ‘I know why they call it breakbone fever.’

It felt like her insides were ‘aching and breaking’, with severe pain in her back. ‘I had no energy and was super weak, which is contrary to whom I am,’ says Gayatri – an energetic and very fit person who exercises six days a week.

A blood test came back positive for dengue fever and she was advised to stay home and hydrate. However, after a few more days of misery, Gayatri checked into hospital where she was put on a saline drip. He platelet count had dipped dramatically and doctors wanted to be sure she would pull through. She also used several natural remedies including coconut water, lime juice, papaya leaf just and plenty of water.

It took four days to shake off the fever and 10 days of rest to recover fully. Two weeks later, Gayatri was on a flight to London and was feeling fine again.

She says she has many friends who suffered the same fate – some of whom have had dengue multiple times. These days she takes every precaution to avoid mosquito bites, even though it can mean wearing long-sleeves in the Mumbai heat. She also burns dhoop – a kind of incense popular in India – and ensures that her home is fumigated regularly.

‘I spray myself like a maniac and try to wear long pants and long-sleeved shirts – which is not easy in hot and humid Mumbai,’ she explains. ‘Basically, I just use mosquito repellent and when I see a mosquito, I flee!’

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Avoid serious complications and keep your community safe from dengue fever by keeping dengue at bay. Click below to download the dengue toolkit.

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Paraná State rolls out the final wave of its dengue immunization program

Health authorities in the Paraná State of Brazil are embarking on the third stage of a public dengue immunization program targeting individuals 9-44 years of age, the first public initiative of its kind in the Americas. The community-based vaccination campaign began on September 20 and will run until late-October in 30 municipalities in Paraná where dengue burden has been high, according to the local Secretary of Health.

More than 300,000 people have received the dengue vaccine in the two previous campaigns as part of the public vaccination program that kickstarted the Paraná dengue battle a year ago. With an initial target of 500,000 people, Parana reported a 60% coverage rate for the first dose.

Almost 2.3 million people suffered from dengue in 2016 in Latin America. Dengue, often nick-named ‘break-bone fever,’ can lead to painful disease marked by fever, headache, and lasting malaise. Today, there is no specific treatment for dengue, which can deteriorate unpredictably into severe dengue that can be deadly.

The World Health Organization recommends integrated dengue prevention and management strategies in endemic countries. As part of integrated public health interventions against the disease, the potential value and impact of dengue vaccination are significant. The WHO has recommended that countries with high dengue burdens consider vaccine introduction.

The first and only vaccine against the four dengue serotypes came into the world in 2015, being registered in Mexico, the country with one of the highest number of cases in the Americas. The vaccine has been approved in 19 countries around the world and is now available in seven Latin American nations: Brazil, Costa Rica, El Salvador, Guatemala, Mexico, Paraguay, and Peru.

The dengue immunization program in Paraná: an investment in public health

Brazil accounts for 65% of the reported cases in the region, but there are also hundreds of thousands of cases throughout the Americas including in Mexico, Colombia, Paraguay, Peru and the countries of Central America and the Caribbean. Dengue case reports indicate that in Mexico and Brazil, 90% of dengue cases occur in those 10 years of age and older, who represent a highly mobile and social segment of the community.

Image showing how to reduce the dengue burden through traditional vector control methods.

Image courtesy of Malaria Consortium

People infected by dengue lose, on average, six days of work. In addition, up to six months after first contracting dengue, individuals report post-infectious symptoms such as severe exhaustion and weakness, which affect their quality of life. In the Americas, the annual cost of dengue, including losses due to lack of work productivity, is estimated at about $ 1.7 billion.

Economic models show that broad vaccination programs in indicated populations have the potential to reduce dengue’s disease burden by 50% in 5 years.

Michele Caputo Neto, Health Secretary in the state said investing in the Paraná dengue vaccine program will pay off by reducing spending on hospital care as well as keeping people in work and protecting the tourist industry.

He says the dengue immunization program complements – rather than replaces – other anti-dengue measures such as public awareness campaigns and vector control strategies. The Health Secretary said he is proud to be a pioneer in integrating vaccination into Paraná’s anti-dengue arsenal.

Learn more about the true cost of dengue (Infographic)

‘We know that Paraná has the technical capacity and appropriate infrastructure to incorporate a new vaccine in the public system,’ he said. ‘We have one of the best health public systems in this country, and our vaccination campaigns obtain the best coverage. All this gives us the credentials to innovate and go forward in the control of the disease in the State.’

Dengue in Davao: Zarah went to the Philippines for work and wound up in hospital

Zarah Caraan was working in Manila with AIESEC, the youth leadership movement when she had an encounter with a mosquito. What happened next left her with the first-hand experience of dengue in Davao – but hasn’t dimmed her wanderlust

‘I had a weekend off so I decided to go to a nature reserve park near Davao in the southern part of the country,’ she recalls. ‘It had been raining and was very humid – which I later learned was an ideal environment for mosquitoes.’

After a weekend well spent, Zarah got back to her desk where she arranged placements for young people keen to work on AIESEC development projects in the Philippines. It was her second time in the country, having previously worked on a project.

Around a week after the trip to Davao, she began to feel a little unwell. ‘I had flown back to Manila and worked all week and by Friday I was feeling a little low,’ she told Break Dengue. ‘I thought I was just tired or had come down with something mild.’

Tired and suffering from a fever, Zarah spent a day or two in bed – but her symptoms showed no signs of easing. ‘I was getting dizzy and could hardly drink; I started feeling joint pain so I called somebody who immediately suspected that I might have dengue fever’.

On her previous stint in the Philippines, Zarah has seen another volunteer endure a dengue fever infection so she knew that it was serious but not usually fatal. Still, there was a real risk of hospitalization so her next call was to her health insurance company in Sweden. They advised her to go to a large accredited hospital in Manila which is popular with western visitors.

As her symptoms were similar to the flu, the doctor suggested this may be the real cause of her fever and joint pain. However, blood tests showed otherwise. Within a couple of hours, the medical staff confirmed that Zarah had contracted dengue in Davao and advised her to go home, rest and take plenty of fluids.

‘They told me to go to the clinic for a new blood test if I don’t feel better in a couple of days,’ she says. ‘As I was still quite unwell, I had another test later that week and it showed that my platelet levels still hadn’t gone up. The doctors said they would have to admit me to hospital.’

Zarah spent five long days in the hospital on an intravenous drip before being discharged – more than two weeks after she began showing signs of dengue. ‘It was pretty boring!’ she says. ‘I was given IV fluids to help rehydrate me and the hospital staff encouraged me to eat and drink like a normal person. Eventually, they let me go home but it was still another week or two before I was fully recovered.’ more about the world’s first dengue vaccine program

Learn more about the world’s first dengue vaccine program

As a result of her brush with dengue in Davao, Zarah has learned a lot about the disease which affects millions of people every year. ‘I didn’t know much about dengue or malaria before going to the Philippines but have since learned that there are several types of dengue and I suspect that I had the milder type,’ she says. ‘I am acutely aware that I had a very privileged perspective given that I had access to one of the best hospitals in the city. A lot of people die from dengue in the Philippines every year so I am fortunate that I had access to good healthcare.’

The experience of dengue in Davao hasn’t dented Zarah’s commitment to AIESEC projects which aim to deliver on the UN Sustainable Development Goals (SDGs) but has made her wary of mosquitoes. ‘I also heard there is a dengue vaccine so, if that’s available, I would try to get that – but I wouldn’t be put off from traveling.’

AIESEC & Break Dengue: seeds of a new partnership

AIESEC is a youth leadership movement with consultative status at the United Nations Economic and Social Council. Founded by young people in 1948 in the wake of the Second World War, the organization has developed a global network of more than 30,000 people that view youth leadership not as an option but as a responsibility.

Working towards a dengue-free Philippines: a look at the country’s vaccination program

Break Dengue and AIESEC will soon reveal an exciting new partnership that gives young people from around the world an opportunity to travel, learn and contribute to making the world a better place.

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Tracking dengue: how Google searchers can help

A new study by researchers at Harvard and Break Dengue shows the power of real-time disease monitoring. It could even enable swifter responses to disease outbreaks

A new research paper published in PLOS Computational Biology, a peer-reviewed scientific journal, reveals how search engines can be used to monitor dengue fever outbreaks in underdeveloped countries.

The paper is authored by scientists at Harvard Medical School, Harvard University, Boston Children’s Hospital and Nicholas Brooke, Executive Director of The Synergist which runs Break Dengue.

It looks at how big data analytics combing Google searchers with official clinical data from government sources can give a quick and accurate picture of dengue outbreaks. The dengue tool builds on previous work by the Harvard team which uses an approach to mathematical modeling known as AutoRegression with Google Search queries (ARGO).

While dengue infects around 390 million people every year, accurate monitoring has proven challenging. ARGO has revived hopes that search engine data could help officials to track disease outbreaks. Previous efforts, such as Google Flu Trends and Google Dengue Trends had not delivered the level of accuracy that had initially been expected.

The new study used a modified version of ARGO to study dengue fever activity in Brazil, Singapore, Thailand, Taiwan, and Mexico. Researchers tracked the most frequently searched dengue-related search terms in each country and collected history dengue data logged by official government health authorities. Both datasets were then put into ARGO which calculated a “near real-time” dengue prevalence value for each country.

By comparing the ARGO estimates to data from five other surveillance tools, it was concluded that ARGO gave a more accurate picture than any other approach for Mexico, Singapore, Thailand, and Brazil. The results for Taiwan were less accurate but the authors attribute this to Taiwan’s less consistent patterns of dengue outbreaks from one year to the next.

The study shows the potential of search engines such as Google to deliver accurate and near real-time data on mosquito-borne diseases in countries where surveillance systems may be weak. The group is now looking at how the dataset could be further bolstered by incorporating information from other sources – such as weather and environmental data.

‘The wide availability of internet throughout the globe provides the potential for an alternative way to reliably track infectious diseases, such as dengue, faster than traditional clinical-based systems,’ says study senior author Mauricio Santillana of Boston Children’s Hospital and Harvard Medical School. ‘This alternative way of tracking disease could be used to alert governments and hospitals when elevated dengue incidence is anticipated, and provide safety information for travelers.’
Adding crowd-sourced data into the mix is also being explored as scientists aim to build a people-powered surveillance tool that could become an invaluable alert system for health authorities and citizens.

The Harvard team is implementing to building blocks that could shape such a platform. One is the Healthmap.org/denguetrends website. The other is Break Dengue’s Dengue Track initiative. This tool offers a user-friendly online chat system to map dengue fever cases. In return, members of the public who contribute their data are given access to toolkits that help to reduce their risk of infection.

The researchers note that the same modeling system could be used to map other infectious and mosquito-borne diseases – including Zika and malaria. Perhaps you and I are the future of disease surveillance.

Perhaps you and I are the future of disease surveillance.

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Dengue protection: what you need to know

New online medical training module explores the role of vaccine in dengue protection

For people living in, or traveling to, areas affected by dengue fever, protection is vital. The most effective ways to reduce the risk of infection have, for decades, been the use of insect repellents and measures to disrupt the mosquito lifecycle.

In recent years, we’ve entered a new era in dengue protection with the arrival of the world’s first dengue vaccine, the first dengue vaccine program, and trials of friendly mosquitoes (genetically-modified mosquitoes). The latter approach is showing promise but more research will be done before it considered for widespread use.

Meanwhile, the first dengue vaccine has been approved in 16 countries and several other dengue vaccines are on the horizon. How best to integrate this new tool into the dengue protection arsenal remains a challenge.

To help manage everything from vaccine delivery to tackling false rumors about vaccine safety, Agence de Médecine Préventive (AMP), a Paris-based NGO with scientific and technical expertise in vaccination, has produced a Dengue Vaccination Toolkit targeting policymakers and vaccine program managers.

But what about doctors? Where can doctors find technical information about dengue vaccination to satisfy their own intellectual curiosity and help answer patients’ questions.

Medical education

Well, now MedScape, a leading source of online information for health professionals, has produced a 45-minute educational module entitled Dengue vaccination: a long-awaited advance in protection.

The continuing medical education (CME) module features four senior experts in dengue fever from Brazil, Mexico, Malaysia and the Philippines. The group looks at the burden of dengue fever and the need for better preventative measures.

‘Incidence is increasing globally,’ says Dr. Marco Safadi, a pediatrician based in Sao Paolo who leads the discussion. ‘Dengue is now the major mosquito-borne illness globally: between three billion and four billion people live in areas where dengue is present.’

The World Health Organization supports the use of dengue vaccines in areas of high burden. However, uptake of the first vaccine has been slower than expected due to a combination of factors. The experts featured in the MedScape educational session called for a ‘paradigm shift’ in how we think about vaccines. They note that the value of vaccines goes beyond preventing infections; it can include reducing the severity of disease and reducing disruption to health services by controlling the scale of outbreaks.

Vaccine confidence

Negative media coverage of vaccination can damage vaccine confidence and reduce the uptake of vaccines. This is a problem that several dengue-endemic countries have faced when considering introducing the vaccine.

Dr. Zulkifli Ismail, Past President and Current Secretary-General of the Asia Pacific Pediatric Association (APPA), said the dengue vaccine has been introduced on the private market in Malaysia but the spread of false rumors online had a negative impact on public perceptions.

A survey of attitudes to dengue vaccination in Malaysia revealed two things: that dengue is a huge public health issue; and that the vaccine faces several major challenges. Of the 799 people who responded to a mobile phone-based survey, 16% reporting having dengue in the past and 73% reported having a friend or relative who had been affected.

However, only 27% knew a vaccine available and one-fifth of these said they would not have the vaccine due to concerns about a lack of data or safety issues. ‘Primary care physicians and other doctors need to educate themselves and be convinced that the vaccine works so that this sentiment can be conveyed to the patients and cascade down to the public,’ according to Dr. Ismail.

The Philippines has faced similar issues, with some negative media coverage of vaccine resistance from some politicians. In other regions, including Parana State in Brazil, public authorities have launched proactive campaigns to bring the vaccine to the public free of charge and provide health professionals with the information required to reassure patients.

Huge untapped potential

The session closed by noting that dengue puts significant pressure on health systems in countries where the disease is endemic. The arrival of dengue vaccines could be a game-changer for dengue protection, as part of a wider integrated strategy to control the circulation of mosquitoes.

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Marathon against dengue: passing the torch in the race against mosquito-borne diseases

A social mobilization campaign is recruiting communities, scientists and governments in a marathon against dengue, Zika, and chikungunya

Beating dengue is a challenge of Olympic proportions – but it’s a marathon, not a sprint. And it is a global race that requires collaboration between a network of stakeholders, according to Pilar Collantes, President of Voces Ciudadanas, a Peru-based organization building alliances between civil society and health authorities in Latin America and the Caribbean.

Collantes wants to bring together a broad coalition to fight diseases spread by mosquitoes. The ‘Marathon Against Dengue, Zika and Chikungunya’ campaign, led by Voces Ciudadanas, is a concerted effort to push-back against vector-borne infections. It begins from the premise that business-as-usual is not enough – the burden of mosquito-borne diseases has risen dramatically in recent decades. New thinking is needed.

infographic showing the economic impact of dengue.

Image courtesy of Malaria Consortium.

“We have to explore comprehensive, audacious and very participative alternatives that involve a higher commitment from the people, especially in schools and communities as well as local, regional and national authorities,” she says.

Collantes says the idea of a ‘marathon’ draws on the Greek myth of Pheidippides, a messenger who ran from Marathon to Athens to announce a great victory. Now, after years of painstaking research on dengue prevention, science is developing tools that can help stop dengue, Zika, and chikungunya in their tracks: vaccines, insecticides, and modern surveillance systems.

“Today, the great race to prevent and control dengue is a reality,” she says. “We encourage states and the scientific community to work together with civil society to prevent these diseases.”

Collantes took this message to the ASEAN Dengue Summit in the Philippines earlier this year to deliver the Torch of the Marathon Against Dengue, Zika, and Chikungunya to the Secretary of Health of the Philippines who embraced the dengue vaccine last year. “What the Philippines has been doing is extraordinary; we encourage them to continue and to broaden this effort to more children in their country.”

She says Voces Ciudadanas wants to emphasize that the arrival of a vaccine is “always excellent news” and cause for celebration. “But it is also necessary to promote its inclusion in the immunization schedules where dengue is endemic.”

That’s why the Philippines must also pass the torch – and its dengue control experience – to others in the region.

Scientific evidence shows that community participation is an essential component in stemming outbreaks of vector-borne diseases, Collantes says. People of all ages have a role to play: Voces Cuidadanas leads a network of children and adolescents in Latin America and the Caribbean. It plans to invite adolescents from Asia Pacific to attend a future meeting.

“The Olympic torch symbolizes the light of knowledge and the delivery of life and hope, to thousands of communities,” she says. “We will unite the countries of the Asia-Pacific to promote the proactive participation of adolescents in the task of preventing vector-borne diseases like dengue, Zika, and chikungunya.”

Dengue in Peru

Dengue fever is a serious public health problem in Peru, says Collantes. “There are several provinces on the Peruvian coast where the number of cases has skyrocketed and the health systems are collapsing,” she says. “The number of dengue-related deaths is high.”

Voces Cuidadanas has been raising awareness of dengue – and how to combat it – through workshops, online social networks, and media interviews. “We believe that the people, including children and adolescents, can and must have a more active role in the prevention and control of dengue,” Collantes says.

The organization has also worked on immunization campaigns in Mexico, Brazil, Panama, Ecuador, Colombia, and Peru, promoting access to vaccines against HPV and hepatitis.

Read how ‘healthy blocks’ are building dengue-free neighborhoods in Argentina

Collantes says the organization is well placed to lead the marathon against dengue, Zika, and chikungunya. “Working on the prevention of one of these diseases in isolation reduces and disperses resources,” she says. “We have to make prevention a global goal, using all the available resources.”

In the race against dengue and other vector-borne diseases, there are many miles left to run.

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Vaccine confidence is key to beating dengue

A global expert in vaccine confidence says attitudes to other vaccines can affect dengue vaccination rates. Media monitoring and can help address fears and dispel myths.

Vaccines are among the top public health inventions of all time. Over the past 50 years, they have eradicated smallpox, pushed polio to the brink of extinction and helped to dramatically reduce childhood mortality.

It’s not just kids that have benefited. Vaccines against flu, meningitis, pneumonia and cervical cancer are protecting people of all ages against infectious diseases.

And yet vaccine confidence cannot be taken for granted.

When Edward Jenner developed the first smallpox vaccine in 1796, people freaked out. They imagined that the material Jenner sourced from a cow to create the vaccine would cause them to grow udders.

But those were less enlightened times. Vaccines proved to be a public health wonder and are now universally accepted. Right?

Not quite. While more people than ever are now vaccinated (thanks to childhood immunisation campaigns) against potentially lethal infectious diseases, there is still plenty of work to do to convince some segments of the public of the value of vaccines.

And, as the 1990s MMR vaccine controversy showed, the combination of flawed science and careless media reporting can make anti-vaccine rumors go viral – sparking outbreaks of preventable disease.

Vaccine confidence studies

So where are we today? A survey of 67 countries found that while most people have a positive view of vaccination, there are still those with lower levels of vaccine confidence. (France – birthplace of Louis Pasteur himself – was the worst!)

Drawing of a hostorical vaccination program taking place.

Image: The Cow-Pock-or-the Wonderful Effects of the New Inoculation

The study was run by Dr. Heidi Larson of the London School of Hygiene and Tropical Medicine. Larson runs the Vaccine Confidence Project and is a renowned expert in how people view vaccines. She says that people’s views on new vaccines are heavily influenced by their opinion on vaccines in general.

This means that when a dengue vaccine is being introduced, not only do health authorities have to deal with practical questions about how the vaccine will be transported, stored and delivered, they have to find a way to ensure that public confidence is not shaken by misplaced concerns based on rumors and myths.

That’s why a new dengue vaccination toolkit on how to introduce dengue vaccines includes a module on rumor management and communication. It’s no use having the vaccines, syringes and health professionals if public demand is low.

Introducing new vaccines

“We have to more homework when introducing a vaccine,” says Larson. “We can be so focused on the specifics of getting rolling out the vaccine itself that we don’t always look at what’s the uptake of other vaccines.”

Trust in science, public health authorities or government can affect vaccine uptake. For example, a crisis in food safety can spill-over into anti-vaccine sentiment.

“China faced a huge scandal with tainted milk which created general mistrust,” says Larson. “Then last year a story broke about a pharmacist who had been repackaging vaccines just as their expiry dates approached – it wasn’t directly to do with vaccines but it undermined the whole system.”

Even the MMR crisis that began in the UK came hot on the heels of a food safety scare where the public felt they had not been given the truth early enough. “We’ve got to lift our heads and scan the whole environment to assess trust in authorities and any other uncertainties that might be in the picture,” she says. “That’s why it’s unwise to launch a vaccine during an election. There’s a risk that it could get caught up in other political issues.”

Some countries, notably those in Scandinavia, have strong and interactive relationships with their publics, resulting in robust levels of public trust. So, when the government introduces a new health initiative, it consults the public and usually secures citizens’ support.

Rumor has it

When it comes to vaccines against dengue fever or HPV which are not targeted at infants, there can be new layers of complexity to consider but trust remains a big factor. Where adolescents might be jointly making decisions about vaccines with their parents, social media can play an influential role.

Larson’s team has been monitoring media and social media for several years, scanning for signals of anti-vaccine sentiment or other indicators of waning trust in health authorities. This, combined with survey results, literature reviews and vaccine uptake rates, can help to give a holistic view of how the public feels about vaccines.

They have found that rumors spread through social networks – online and offline – and can cross borders. Not only can antivaccine stories spread to neighboring countries but myths also travel through linguistic and religious networks. False rumors about the polio vaccine have spread through Muslim networks while tetanus vaccine refusal traveled through Catholic networks from the Philippines to Africa and Latin America.

The ultimate goal is to build a system that can detect dips in vaccine confidence – or the outbreak of false rumors – before they take hold. Larson has been doing this for vaccines such as the pentavalent vaccine and for outbreaks of diseases including Ebola.

In a recent blog post, she noted how Facebook and Whatsapp were a conduit of anti-vaccine messages. By tracking these issues, it could become possible to target communication and engagement campaigns to where they are most needed.

“We are constantly putting out fires,” she says. “The idea of setting up a system to track vaccine confidence was to be able to gain resilience – to sustain trust rather than trying to fix it after it is broken.”