# Human cytomegalovirus seropositivity and its influence on oral rotavirus vaccine immunogenicity: a specific concern for HIV-exposed-uninfected infants

## TL;DR

This study found that human cytomegalovirus (HCMV) infection may reduce the effectiveness of the rotavirus vaccine in HIV-exposed-uninfected infants, but not in the general infant population.

## Contribution

The study identifies a specific impact of HCMV on rotavirus vaccine immunogenicity in HIV-exposed-uninfected infants.

## Key findings

- No overall association was found between HCMV serostatus and rotavirus antibody titers in infants.
- HIV-exposed-uninfected infants with HCMV had a 63% reduction in rotavirus antibody titers.
- The study highlights the need for targeted interventions to improve vaccine efficacy in vulnerable populations.

## Abstract

Oral rotavirus vaccines demonstrate diminished immunogenicity in low-income settings where human cytomegalovirus infection is acquired early in childhood and modulates immunity. We hypothesized that human cytomegalovirus infection around the time of vaccination may influence immunogenicity. We measured plasma human cytomegalovirus-specific immunoglobulin M antibodies in rotavirus vaccinated infants from 6 weeks to 12 months old and compared rotavirus immunoglobulin A antibody titers between human cytomegalovirus seropositive and seronegative infants. There was no evidence of an association between human cytomegalovirus serostatus at 9 months and rotavirus-specific antibody titers at 12 months (geometric mean ratio 1.01, 95% CI: 0.70, 1.45; P = 0.976) or fold-increase in RV-IgA titer between 9 and 12 months (risk ratio 0.999, 95%CI: 0.66, 1.52; P = 0.995) overall. However, HIV-exposed-uninfected infants who were seropositive for human cytomegalovirus at 9 months old had a 63% reduction in rotavirus antibody geometric mean titers at 12 months compared to HIV-exposed-uninfected infants who were seronegative for human cytomegalovirus (geometric mean ratio 0.37, 95% CI: 0.17, 0.77; P = 0.008). While the broader implications of human cytomegalovirus infections on oral rotavirus vaccine response might be limited in the general infant population, the potential impact in the HIV-exposed-uninfected infants cannot be overlooked. This study highlights the complexity of immunological responses and the need for targeted interventions to ensure oral rotavirus vaccine efficacy, especially in vulnerable subpopulations.

Among rotavirus vaccinated infants, there was no evidence of an association between HCMV-IgM serostatus at 9 months with RV-IgA titer at 12 months (GMR 1.01, 95%CI: 0.70, 1.45; P  = 0.976). However, HIV-exposed-uninfected infants who were HCMV-IgM seropositive at 9 months old had a 63% reduction in RV-IgA geometric mean titers at 12 months compared to HIV-exposed-uninfected infants who were HCMV-IgM seronegative (geometric mean ratio 0.37, 95%CI: 0.17, 0.77; P  = 0.008). Created with BioRender.com

Graphical Abstract