Countries which suffer from malaria present strikingly low rates of COVID-19 deaths. Given the epidemiological and human interrelations between the two diseases, there is a danger that the global struggle against malaria will suffer from the diversion of resources to deal with the new coronavirus.
The exceptional strain that the pandemic is putting on many health systems has indirect consequences. A Global Fund survey in June raised the possibility of 382,000 additional malaria deaths in 2020 versus 2018 as a result of COVID-19. The testing and treatment of people with malaria depends on the availability of health workers, who may be unable to travel due to lack of COVID-19 protective equipment, the survey found.
The impact on malaria is unlikely to end this year. According to a study by Alexandra B. Hogan and colleagues in The Lancet, deaths from malaria may increase by 36% in the countries with the heaviest burden of the disease over the next five years as a result of COVID-19. The biggest risk of a resurgence of malaria is from the interruption of planned mosquito net distribution campaigns, the study finds.
The disruption caused to anti-malaria campaigns by new, unexpected pandemics is well known. The UK Charity Malaria No More points to a massive resurgence in malaria in Guinea, Liberia and Sierra Leone during the Ebdola pandemic in 2014-2016. Malaria No More says that current investments to fight malaria prevent almost 100 million cases a year and save nearly 600,000 lives.
Science not Politics
The relationship between the prevalence of COVID-19 and malaria is intriguing, and offers clues to the puzzle of why some countries are much more affected than others by coronavirus.
Some have looked at national cultures in Asia, such as in Thailand and Japan, to explain relatively low rates of COVID-19 infection. Others have sought to suggest that Communist countries have done better than capitalist ones in combating the spread of the sickness – while ignoring inconvenient countries such as Thailand which is not Communist and has very low COVID-19 incidence.
Explanations based on national cultures or political ideology will not work. In Southeast Asia, Cambodia, Laos, Vietnam, Thailand and Burma all have very low or zero levels of death from COVID-19. These countries defy any straightforward attempt to classify them. But combining history, geography, archaeology, hematology and genetics opens up more promising avenues.
The French hematologists Jean Bernard and Jacques Ruffié published “Hématologie Géographique” in 1966. They showed that many populations in South-East Asia carried hemoglobin E (HbE) in their blood. This is a genetic characteristic of populations descended from the Khmer Empire, which was at its height in the 12th and 13th centuries. Hemoglobin E is a factor of natural selection which has historically protected the populations which have it against the most serious forms of malaria.
Bernard writes that the “geography of hemoglobin E and that of the monuments of Khmer art are almost identical. This is a remarkable correspondence. The limits of the ancient Khmer empire were until now defined by archaeology. They can today be defined by hematology. The limits are about the same.”
There are striking pathogenic similarities between malaria and COVID-19, especially in the shared symptoms in the most serious cases of the two illnesses. There is also a virus with animal origins which infects the parasite responsible for malaria, and which has a genomic sequence quite similar to that of the new coronavirus responsible for COVID-19. This could signify that the malaria-related virus might confer a form of immunity against COVID-19.
In India, areas where malaria is endemic, the centre-east and the north-east, seem to resist COVID-19 much better than the rest of the country. In north-east India, the seven small states where the most of the populations carry hemoglobin E like the neighbouring populations of Burma, seem to be the most spared by COVID-19, with exceptionally low or zero deaths. In Africa, the northern and southern extremes of the continent have suffered much worse from COVID-19 than the malarial sub-Saharan Africa.
Further, the infectious malarial agent, a parasite called “Plasmodium” and the new coronavirus have similar impacts on the blood. They infect or modify red blood cells and both illnesses lead, in the most serious cases, to identical complications such as the formation of blood clots leading to thrombosis, pulmonary embolism and strokes. Besides, people with blood group O as defined by their red blood cells, seem to be less susceptible than others to COVID-19. Specific genes have been identified and their role explained. This suggests that further research into the role of genetic factors in resistance to COVID-19 will greatly help in the search for treatments and a vaccination.
The danger is that countries which have malaria will slip further down the international health agenda, especially if they strive to maintain rates of infection from COVID-19 at their current low levels. It would be a tragedy if populations which seem relatively protectively against COVID-19 suffer an increase in malaria deaths because of the new pandemic.
COVID-19 exists in addition to, not instead of, the world’s existing health problems. It is clear that the progress that has been made against malaria is in danger as resources are diverted to tackling COVID-19. The World Health Organization (WHO) says that in a worst-case scenario, the number of malaria deaths in sub-Saharan Africa this year could double versus 2018.
This would mean a return to malaria mortality levels last seen 20 years ago. Policymakers and donors must ensure that they are not allowing progress on malaria, as well as HIV and tuberculosis, to unravel as the fight against COVID-19 continues.
By Sam Rainsy