Helmet infection provides protection against SARS-CoV-2

A study examined the impact of previous infection with the helmet parasite Nippostrongylus brasiliensis on the immune response to SARS-CoV-2. Mice that had cleared a previous helmet infection showed improved survival rates and reduced weight loss following SARS-CoV-2 infection compared to mice without helmet infection. The protection was found to be lung-specific, as a different parasite infecting the intestine did not confer the same benefits. The study revealed that the improved immune response was mediated by CD8 T cells, which were more effectively recruited to the lung in previously infected mice. Alveolar macrophages were found to play a crucial role in this process. The macrophages produced type 2 cytokines, resulting in a shift in the lung immunological environment. The study sheds light on the interaction between previous parasite infection and subsequent lung pathogens, providing potential insights into disease susceptibility and immune response modulation.