Cape Town - The scientific complexities around Covid-19 and vaccines were unpacked by the National Institute for Communicable Diseases (NICD).
The NICD held a briefing on Covid-19 which forms part of regular sessions titled, “Covid-19: Decoding the science to provide a more comprehensive understanding of the pandemic”.
Principal medical scientist Dr Jaishree Raman said that over the two years of the Covid-19 pandemic, malaria cases had declined.
“But with the relaxation of travel restrictions and increased border movement, we’ve seen an increased number of cases and an increased number of deaths.”
KwaZulu-Natal went from reporting fewer than 30 malaria cases over the past few months to 97 cases this month, and Mpumalanga went from fewer than 100 cases in December to 250 cases this month.
“There are a number of malaria cases that are being diagnosed late or being missed, and it’s really driven by the fact that both Covid-19 and malaria share very similar symptoms in terms of being very non-specific. That includes fever, flu-like illness, headaches, fatigue, muscle and joint pain,” Raman said.
Patients were presenting at health-care facilities late, thinking they had the flu or Covid-19. They were not considering malaria.
“And this is a huge problem because untreated malaria rapidly progresses to severe disease, and unfortunately often with fatalities in non-immune-rich individuals, which is all of South Africa.”
Anyone who lives in, or has travelled to, a malaria area in the past six weeks must be tested using a rapid diagnostic test or microscopy, according to treatment guidelines. Malaria-endemic areas in South Africa include the north-eastern border regions shared with Botswana, Zimbabwe, Mozambique, and eSwatini.
Raman raised awareness on “taxi (Odyssean) Malaria”, which is infections in individuals with no recent travel history to a malaria area, caused by a “hitch-hiking” mosquito. These cases are associated with high fatality rates due to delayed detection and treatment.
Research Professor Penny Moore said immune response could be divided into two arms – namely antibody immunity and T cells.
“Antibodies are these Y-shaped molecules, and what they do is they bind directly to SARS-CoV-2 in this case, and then prevent SARS-CoV-2 from being able to infect the cells at all.
“They block any infection from happening, and this is what is called neutralisation. Should the antibodies not be able to do the job for whatever reason, then there’s a back-up aspect, and that’s our T cells.”
Moore said vaccines were slightly less able to prevent infection by Omicron than previous variants, as the antibodies did not bind as well, increasing the risk of breakthrough infections after vaccinations.
Covid-19 vaccines prevented severe illness and hospitalisation by Omicron, probably because of our T cells, said Moore.
Professor Cheryl Cohen said the country had a robust surveillance system to monitor the emergence of new variants, called the NGS-SA (Network for Genomic Surveillance in South Africa).
“It's a collaboration between many different universities, academic groups, the National Health Laboratory Service and the NICD.
“What this collaboration does is, they sequence a subset of all the cases of Covid-19 diagnosed in South Africa every week, and they try really hard to get it to be a representative subset of all the different provinces, and that’s really how we track the emergence of new variants.”