Serum and Salivary IgG and IgA Response After COVID-19 Messenger RNA Vaccination.

Importance: There is still considerable controversy in the literature regarding the capacity of intramuscular messenger RNA (mRNA) vaccination to induce a mucosal immune response. Objective: To compare serum and salivary IgG and IgA levels among mRNA-vaccinated individuals with or without previous SARS-CoV-2 infection. Design, Setting, and Participants: In this cohort study, SARS-CoV-2-naive participants and those with previous infection were consecutively included in the CoviCompare P and CoviCompare M mRNA vaccination trials and followed up to day 180 after vaccination with either the BNT162b2 (Pfizer-BioNTech) vaccine or the mRNA-1273 (Moderna) vaccine at the beginning of the COVID-19 vaccination campaign (from February 19 to June 8, 2021) in France. Data were analyzed from October 25, 2022, to July 13, 2023. Main Outcomes and Measures: An ultrasensitive digital enzyme-linked immunosorbent assay was used for the comparison of SARS-CoV-2 spike-specific serum and salivary IgG and IgA levels. Spike-specific secretory IgA level was also quantified at selected times. Results: A total of 427 individuals were included in 3 groups: participants with SARS-CoV-2 prior to vaccination who received 1 single dose of BNT162b2 (Pfizer-BioNTech) (n = 120) and SARS-CoV-2-naive individuals who received 2 doses of mRNA-1273 (Moderna) (n = 172) or 2 doses of BNT162b2 (Pfizer-BioNTech) (n = 135). The median age was 68 (IQR, 39-75) years, and 228 (53.4%) were men. SARS-CoV-2 spike-specific IgG saliva levels increased after 1 or 2 vaccine injections in individuals with previous infection and SARS-CoV-2-naive individuals. After vaccination, SARS-CoV-2-specific saliva IgA levels, normalized with respect to total IgA levels, were significantly higher in participants with previous infection, as compared with the most responsive mRNA-1273 (Moderna) recipients (median normalized levels, 155 × 10-5 vs 37 × 10-5 at day 29; 107 × 10-5 vs 54 × 10-5 at day 57; and 104 × 10-5 vs 70 × 10-5 at day 180 [P < .001]). In contrast, compared with day 1, spike-specific IgA levels in the BNT162b2-vaccinated SARS-CoV-2-naive group increased only at day 57 (36 × 10-5 vs 49 × 10-5 [P = .01]). Bona fide multimeric secretory IgA levels were significantly higher in individuals with previous infection compared with SARS-CoV-2-naive individuals after 2 antigenic stimulations (median optical density, 0.36 [IQR, 0.16-0.63] vs 0.16 [IQR, 0.10-0.22]; P < .001). Conclusions and Relevance: The findings of this cohort study suggest that mRNA vaccination was associated with mucosal immunity in individuals without prior SARS-CoV-2 infection, but at much lower levels than in previously infected individuals. Further studies are needed to determine the association between specific saliva IgA levels and prevention of infection or transmission.

Long-term immunogenicity of two doses of 2009 A/H1N1v vaccine with and without AS03(A) adjuvant in HIV-1-infected adults.

OBJECTIVE: In immunocompromised patients, alternative schedules more immunogenic than the standard influenza vaccine regimen are necessary to enhance and prolong vaccine efficacy. We previously reported that the AS03A-adjuvanted 2009 A/H1N1v vaccine yielded a higher short-term immune response than the nonadjuvanted one in HIV-1-infected adults. This study reports the long-term persistence of the immune response. DESIGN AND METHODS: In a prospective, multicenter, randomized, patient-blinded trial, two doses of AS03A-adjuvanted H1N1v vaccine containing 3.75 µg haemagglutinin (n = 155; group A) or nonadjuvanted H1N1v vaccine containing 15 µg haemagglutinin (n = 151; group B), were administered 21 days apart. Haemagglutination inhibition and neutralizing antibodies were assessed 6 and 12 months after vaccination. RESULTS: In group A and B, the seroprotection rates were 83.7 and 59.4% at month 6, and 70.4 and 49.3 at month 12, respectively. In a multivariate analysis, persistence of seroprotection 12 months after vaccination was negatively associated with current smoking (odds ratio = 0.6, P = 0.03) and positively related with the AS03A-adjuvanted H1N1v vaccine (odds ratio = 2.7, P = 0.0002). CONCLUSION: In HIV-1-infected adults, two doses of adjuvanted influenza vaccine induce long-term persistence of immune response up to 1 year after vaccination.