Across history, humans have successfully eradicated only one disease — smallpox. Successful eradication was made easier given that the disease was easy to diagnose because there were no asymptomatic cases and strong surveillance mechanisms were introduced. But perhaps the biggest contributing factor was the availability of a safe and effective vaccine.
We know the importance of an effective vaccine, given our current race to protect the global population from COVID-19. The pandemic has activated an unprecedented collective pooling of investment and intelligence, as well pioneering research, towards finding a vaccine that would put an end to the death and disruption caused by the emergence of this new virus. Remarkably, less than a year later, a viable vaccine is now starting to roll out in countries around the world. The scientific response to COVID-19 has been unique in its speed but — as we have seen with smallpox — there are other examples where a safe, available vaccine alongside rigorous data-driven planning, political will at all levels and adequate funding has enabled huge progress to eradicating a pervasive health threat.
Today, we are skirting tantalisingly close to the eradication of polio, thanks to the efforts of a global partnership, The Global Polio Eradication Initiative (GPEI). Whilst the aim to eradicate the disease entirely by the year 2000 was not met, enormous progress has been made and cases have decreased by over 99 percent. In 1985, Rotary International launched a global effort to immunise the world’s children against polio, which was followed by the establishment of the Global Polio Eradication Initiative (GPEI) in 1988.
As of 2017, the virus remains active in three countries in the world – Afghanistan, Pakistan and Nigeria. In recent years, polio cases have occurred almost exclusively in countries affected by conflicts. As immunisation efforts are a joint collaboration with national governments and the World Health Organization (WHO), it can be difficult to carry out vaccinations in times of conflict. In India, polio eradication was deemed particularly challenging, owing to a high population density and high levels of migration and yet, it was declared polio-free in 2014, thanks to the combination of vaccination programmes, community mobilisation, robust surveillance and consistent and sustained efforts of key global health actors.
How has the near-eradication of polio been achieved?
- The global effort to eradicate polio is perhaps the largest, internationally-coordinated public health drive in history (prior to COVID-19); The GPEI is led by national governments and five partners: WHO, UNICEF, Rotary International, the Bill & Melinda Gates Foundation and US Centers for Disease Control and Prevention.
- An effective vaccine was developed and over 2.5 billion children have been vaccinated.
- There are three strains of poliovirus, none of which can survive for long outside the body, and if the virus cannot find an unvaccinated person to infect, it will die out.
- There has been a sustained financial effort to eradicate polio, with investment drives from key donors such as Rotary International.
- In countries where it has been eradicated, there has been political will at all levels.
How does the fight against malaria compare?
The number of countries successfully eradicating malaria is increasing. Since 2000, 21 new countries have eliminated malaria (three consecutive years of zero indigenous cases) and 27 countries have reported fewer than 100 cases. The Greater Mekong Subregion (GMS) has seen particular success; malaria cases have reduced by 90 percent since 2000, with an accelerated decrease in P. falciparum cases – notable in view of the threat posed by antimalarial drug resistance in the area. Surveillance systems and community mobilisation, appropriate to the local context, alongside the mass distribution of long-lasting insecticidal nets (LLINs), early diagnosis and treatment with safe, effective drugs, community level health workers trained to diagnose and treat malaria and social and behavioural change (SBC) interventions to encourage early treatment seeking have also helped to drive down cases.
There have also been some long-awaited developments towards a malaria vaccine. The RTS, S malaria vaccine implementation pilot which launched in Ghana, Kenya and Malawi last year is a key milestone. However, with relatively low efficacy rates in clinical trials (preventing only 39 percent of malaria cases in children receiving four doses), it will realistically form only a part of a much broader range of interventions and approaches needed to make significant strides towards elimination, especially in Africa.
Despite some of the positive progress, global gains in combatting malaria have levelled off in recent years. Health systems in malaria endemic countries face multiple challenges, including a lack of domestic investment, and despite international support to deliver preventative strategies, promote early diagnosis and provide effective treatments, malaria elimination still lies a long way off in many countries.
Some of the challenges in the fight against malaria
- There is no wide-spread, effective vaccine.
- In Africa and some countries in Asia, surveillance systems are still not fully developed (malaria is not a notifiable disease).
- Access to early diagnosis and treatment for remote or poverty-affected populations is poor.
- Drug and insecticide resistance is affecting the efficacy of malaria treatments and vector control interventions in some regions.
- Asymptomatic infections are common and difficult to detect.
- Elimination of the vector may be impossible.
- Decline in political will in countries and among international donors as malaria declines may result in resurgence of the disease. Even countries that have successfully eliminated malaria are at risk, unless they maintain good surveillance and prevent reintroduction where there is receptivity and vulnerability.
There are easy comparisons to draw between polio elimination and malaria elimination — in particular the nature of asymptomatic infections and the role poverty has to play in tackling the diseases. But whilst polio is a viral infection with no specific treatment, only prevention, there are a number of highly effective tools and approaches to address malaria which need to be utilised.
We need to accelerate progress towards malaria elimination by increasing investment in the right tools and approaches, strengthening malaria surveillance and ensuring equity in access to quality health services. Increased momentum in the development of malaria vaccines should remain a priority, particularly with the emerging biological threats that could erode some of the gains made in the past 20 years. A regional, cooperative, joined-up approach, such as that shown by the Asia Pacific Malaria Elimination Network (APMEN) has proven to be extremely effective given the success in the GMS over the last few years.
A robust, coordinated effort like this, with effective surveillance and uninterrupted funding is needed everywhere so that alongside polio, we can be in a position to eliminate malaria globally.
Olivia Carlin is Communications Officer at Malaria Consortium