Does survival confer subsequent immunity?
Only partially and for a duration that is a function of the intensity and frequency of prior infections. In areas with seasonal or epidemic malaria where disease is infrequent, adequate protective immunity may never build uP. In endemic areas with high levels of transmission, newborn children are protected in their first months of life by the antibodies of their immune mothers. After that they gradually develop their own immunity over the years, if they do not die from the disease. The immunity is reversible, and fully “immune” adults who leave malarious areas are known to return to a state of non-immunity over a period of 1 to 2 years. In persons with sickle cell anaemia or the sickle cell trait, the abnormal haemoglobin S offers some protection against Plasmodium falciparum infection.
