Seroprevalence of neutralizing antibodies against the respiratory syncytial virus in healthy adults in Guangzhou, southern China

Abstract Respiratory syncytial virus (RSV) is the major cause of pneumonia and bronchiolitis in infants and young children and mediates substantial morbidity and mortality in the elderly and immunocompromised globally. The development of a safe and effective RSV vaccine and an optimized neutralizing antibody (NAb) with strong virus‐neutralizing activity is appealing. To gain some detailed knowledge of the humoral immune response to RSV subgroup A (RSV‐A) and RSV‐B, we investigated the seroprevalence of pre‐existing NAbs by using the microneutralization assay in healthy adult from Guangzhou, southern China. We found that the overall seropositive rate was 84.86% for anti‐RSV NAbs. Furthermore, the seropositive rates were 68.47% and 73.61% for anti‐RSV‐A NAbs and anti‐RSV‐B NAbs, respectively. In addition, although the seropositive rates and NAb levels were not associated with the blood type, type AB individuals displayed higher seropositive rates for anti‐RSV‐A NAbs with high titer (≥ 288) and anti‐RSV‐B NAbs, especially those with moderate titer (≥ 72 to < 288). The seropositive rates and titers were comparable between anti‐RSV‐A NAbs and anti‐RSV‐B NAbs in the AB blood type group. Interestingly, only when the NAb titer of the serum to RSV‐A was not less than 288, was it not less than 18 to RSV‐B, and vice versa. These results would be helpful for a better understanding of the human serum NAb responses to RSV‐A and RSV‐B.