Sex, Immunity and Influenza

Abstract

Sex-specific endocrine and immune responses are widely recognized to account for differential disease outcomes between females and males. Surprisingly, sex-specific risk assessments for influenza, a viral pathogen that affects human populations worldwide through seasonal epidemics and irregular occurring pandemics, are sparse and-if available-ambiguous. To date, this precludes proposing an unequivocal sex-dependent susceptibility to influenza. However, one undisputable observation recurrently confirmed during influenza seasons of the last decades is the significantly increased risk for pregnant women. This increased risk is likely attributable to the contradictory demands for the maternal immune system to adapt to pregnancy and to simultaneously mount an immune response to clear the influenza virus infection. Here, we review published evidence on the potential association between sex on influenza risk and propose that future epidemiologic studies should carefully dissect surveillance data for sex-specific effects. Moreover, we propose potential mechanisms involved in enhanced risk for severe influenza during pregnancy that could be studied to identify causal pathways.

Results of a pilot study using self‐collected mid‐turbinate nasal swabs for detection of influenza virus infection among pregnant women

“…By randomly assigning participants to three delivery methods, we increased our confidence that the acceptability of the method is not limited to a specific delivery approach. Our focus on pregnant women also adds to the value of our pilot, as innovative community‐based methods are especially needed to address many unanswered questions about the epidemiology of influenza and vaccine effectiveness among pregnant women …”

Vaccination evokes gender-dependent protection against tularemia infection in C57BL/6Tac mice

“…The existence of gender bias in the immune response to infectious diseases is further supported by numerous in vivo studies focused on Mycobacterium marinum [10], Streptococcus pneumoniae [11], Streptococcus pyogenus [12], Plasmodium chabaudi [13], and Mycoplasma pulmonis [14]. A similar tendency has been seen in humans against numerous pathogens including: Mycobacterium tuberculosis [15], Influenza virus [16] and community-acquired pneumonia [17] in which men are more susceptible than women.…”

Sex differences in HIV-1-mediated immunopathology

“…A strong sex bias is observed for many autoimmune diseases(2), which are much more common in females, including autoimmune thyroid diseases, systemic sclerosis, systemic lupus erythematosus. Furthermore, the incidence and severity of several microbial infections, including malaria and tuberculosis(3), influenza(4), hepatitis(5) and HIV-1(6) are different between the sexes(7). In HIV-1 infection, clinical studies have shown faster disease progression and stronger immune activation in females compared to males for the same level of viral replication, as well as better control of initial viremia in women during primary infection.…”