Sustained salivary IgG but short-lived IgA responses following primary and booster MenACWY-TT vaccination in older adults.

In 30 seconds

This phase IV, open-label clinical trial assessed salivary antibody responses after primary MenACWY-TT vaccination in 216 adults aged 65–85 years; 100 participants received a booster one year later. Primary vaccination significantly increased salivary IgA and IgG against all four serogroups. IgA returned to baseline within 1–2 years, while IgG remained elevated for at least 2 years. The booster increased salivary IgG but did not boost IgA, indicating different persistence and booster responsiveness for these antibody classes.

Key findings

• Primary vaccination significantly increased salivary IgA and IgG concentrations for all serogroups.
• Salivary IgA returned to baseline within 1–2 years, whereas IgG remained elevated for at least 2 years.
• Booster vaccination enhanced salivary IgG but failed to boost salivary IgA responses.
• Salivary IgG correlated strongly with serum IgG, while salivary IgA correlated with secretory component levels.

Why it matters

The findings show that antibody responses in saliva after parenteral MenACWY-TT vaccination differ by antibody class in older adults. This distinction may inform understanding of mucosal immune responses relevant to meningococcal carriage, while the study does not establish whether these salivary responses prevent colonization or invasive disease.

What to keep in mind

The study measured antibody concentrations and does not report whether these responses reduced meningococcal carriage or disease.