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The following is a summary of “Association of pneumococcal conjugate vaccination with SARS-CoV-2 infection among older adult recipients of COVID-19 vaccines: a longitudinal cohort study,” published in the August 2024 issue of Infectious Disease by Lewnard et al.

Researchers conducted a retrospective study assessing the potential impact of pneumococcal conjugate vaccines (PCVs) on COVID-19-related outcomes in adults with prevalent immunity against SARS-CoV-2, given the established link between pneumococcal carriage and increased acquisition and duration of SARS-CoV-2 infection.

They involved adults aged 65 and older in the Kaiser Permanente Southern California (KPSC) healthcare system who had received at least 2 COVID-19 vaccine doses. The risk of SARS-CoV-2 infection was compared (January 1, 2021, and December 31, 2022) among patients who received PCV13 and patients who did not. The aHR using Cox proportional hazards models and applied multiple strategies was estimated to address potential bias from differing test-seeking behaviors.

The results showed an aHR of 0.92 (95% CI: 0.90-0.95) for confirmed SARS-CoV-2 infection in PCV13 recipients vs. non-recipients, corresponding to prevention of 3.9 (2.6-5.3) infections per 100 person-years. After receiving 2, 3, and ≥4 COVID-19 vaccine doses, the aHRs were 0.85 (0.81-0.89), 0.94 (0.90-0.97), and 0.99 (0.93-1.04), respectively. The aHR for individuals unvaccinated in the previous 6 months was 0.90 (0.86-0.93), compared to 0.94 (0.91-0.98) for patients vaccinated within 6 months. Additionally, the aHR was 0.92 (0.89-0.94) for patients without a history of SARS-CoV-2 infection vs. 1.00 (0.90-1.12) for patients with prior documented infection.

Investigators concluded that PCV13 demonstrated modest protection against SARS-CoV-2 infection among older adults fully vaccinated against COVID-19, with greater protective effects observed in individuals with potentially weaker immune responses to SARS-CoV-2.

Source: academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiae387/7727478