Most of the surveys conducted in India seem to indicate that seropositivity appears to be higher in women than in men. The August sero-survey in Delhi found that the seropositivity rate (SPR) among females was higher at 24.2 percent compared to 21.63 percent among males.
It has also been found to be marginally higher in Mumbai as well. However the age-wise prevalence was found to be comparable in both males and females in Mumbai. Since the data has not been corrected for the lower sensitivity of 93 percent of the CLIA kits, these figures represent a conservative lower estimate, notes the report.
Levels of activation of immune cells are also higher among women than in men, studies suggest. Women generally produce higher levels of antibodies that remain in the circulation longer. The immune regulatory genes encoded by the X chromosome in female gender cause lower viral load levels and less inflammation than in men.
The lower susceptibility to viral infections among women is attributed to a higher innate immunity, steroid hormones and certain factors related to sex chromosomes. Toll-like receptor 7 (TLR7) is higher among women than in men and its biallelic expression leads to higher immune responses and increases the resistance to viral infections. TLR7 is expressed in innate immune cells which recognize single-strand RNA virus by promoting the production of antibodies against the virus and the generation of pro-inflammatory cytokines, including IL-6 and IL-1 family members.