Acquisition and maintenance of immunity to malaria
Anna Färnert researches malaria, above all how the immune system’s response to the disease is affected by different factors. She has shown, for example, that immunity disappears much more quickly than previously thought and that repeated infections by different strains are important for the immune system to protect against the disease.
Anna Färnert, Professor of Infection Medicine, specialising in Tropical Medicine, at the Department of Medicine, Solna
In areas where malaria transmission is high, older children and adults are largely immune to the disease. Anna Färnert studies how this immunity is acquired and maintained. Her research improves understanding of what a vaccine has to contain and how often it has to be given to be effective.
Professor Färnert’s group has shown that exposure to several strains of the malaria parasite gives rise to a broader immune response and thus better protection against the disease.
“Those with the best immunity have low levels of the parasite in their blood, and often multiple strains,” says Professor Färnert. “This suggests that the presence of the parasite keeps the immune system active.”
By studying immunity in people who have emigrated from malaria-affected areas, Professor Färnert has been able to demonstrate that protection against severe malaria does not last a lifetime, as previously thought, but degrades as time passes.
“Malaria patients of African origin who have lived for more than 15 years in Sweden are just as likely to develop severe symptoms as those who were born in Sweden,” she says.
However, her research also shows that an immunological memory to certain antigens of the parasite is highly persistent, even in people who have only been infected once. Her research now focuses on identifying which factors are needed to obtain and maintain protection against the disease.
Professor Färnert’s group is also studying the epidemiology of malaria and different strains, how repeated and chronic malaria infections affect the body and biological ageing, and how other diseases, such as diabetes and obesity, as well as management and treatment influence the risks associated with malaria.
Text: Anders Nilsson, first published in "From Cell to Society" 2016