Why So Few Cases of COVID-19 in Papua New Guinea?
What is the effect of climate and temperature on COVID-19 transmission? That is the trillion dollar question as recently highlighted in an article by Think Global Health. In another article published in The Jarkata Post, a team of researchers concluded from their data that high temperatures and humidity can limit COVID-19 transmission in Indonesia. BUT can be exacerbated by people mobility and increased social interaction.
As of the 11th of May 2020 Papua New Guinea (PNG) has reported only 8 cases of COVID-19 and Fiji 18 cases. Other pacific island countries are also reporting low numbers and are reported as sporadic and/or cluster cases. Community transmission has not been established in the pacific island countries. Guam so far as the highest reported number of cases with 147 cases also occurring as clusters but no established community transmission. A similar pattern is emerging in the African continent, although few countries have community transmission.
So a key question that public health physicians and researchers will be engaging in the coming months is does climate, temperature, humidity and other climatic/weather factors influence the transmission of COVID-19? From the emerging data and preliminary research reports, it appears climate does play a role.
Questions have been asked as to whether immunity to tuberculosis indirectly protects against COVID-19. There are 2 clinical trials under way to answer that question. The trials are trying to find out if vaccination with BCG (the TB vaccine) protects against COVID-19. Another interesting question that comes to my mind is Does immunity to malaria protect against COVID-19? There seems to be a relationship between TB immunity (BCG vaccination or exposure to TB acquiring natural immunity), malaria immunity and COVID-19 infection. From preliminary research data it appears that immunity to TB and malaria protects against COVID-19 infection.
In an article published by researchers from India they claim to show that malaria free countries had more people dying from COVID-19 compared to countries where malaria is endemic. Also they concluded from their analysis that countries with higher BCG coverage had less people dying from COVID-19 compared to countries with low BCG coverage. However, they cautioned that this relationship observed in their data is non-linear, meaning the relationship is not a simple correlation effect but rather there appear to be other unknown factors also at play. They also observed that exposure to chloroquine in malaria endemic zones might have a protective effect against COVID-19.
I read the article and I know that this area of research will intensify soon.
And I am just wondering if PNG is reporting so few COVID-19 cases due to some protective effect exerted by malaria and TB immunity in the PNG population. The research prospect into this area is beckoning and certainly something I want to get my hands on. It may open new area of research into looking at the relationship between immunity to parasites and indirect immunity to viruses. Let us wait to see but for now continue to practice social distancing, hand hygiene and wear facial masks to protect against COVID-19.
Dr Rodney Itaki, MBBS, BMedSci
Pacific Family Health Journal features every Wednesday on PNGBUZZ.COM
View original article on Dr Itaki’s blog here