Naslov
Slower Waning of Anti-SARS-CoV-2 IgG Levels Six Months after the Booster Dose Compared to Primary Vaccination

Autori
Zember, Sanja ; Bodulić, Kristian ; Balent, Nataša Cetinić ; Mikulić, Radojka ; Markotić, Alemka ; Đaković Rode, Oktavija

Izvornik
Vaccines (2076-393X) 10 (2022), 11; 1813, 10

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
anti-SARS-CoV-2 antibodies ; BNT162b2 vaccine ; booster dose ; healthcare workers ; Croatia

Sažetak
Anti-SARS-CoV-2 IgG titer decreases rapidly after primovaccination, leading to a mandatory booster vaccination. We analysed anti-SARS-CoV-2 Spike RBD IgG levels (positive ≥ 50 AU/mL) in 405 healthcare workers (3010 sera) who received a booster dose (BD) 9 months after two-dose BNT162b2 primovaccination. Median antibody titer at the time of BD (582.6 AU/mL) was 1.7-fold and 16.4- fold lower than the peak titer after the first (961.5 AU/mL) and the second vaccine dose (SVD) (10, 232.6 AU/mL), respectively. One month after vaccination, IgG titer increased 40.6-fold after BD compared with a 10.8-fold increase after primovaccination. Three months after vaccination, post-booster antibodies decreased significantly slower (2.2-fold) than after primovaccination (3.3-fold). At six months, antibodies decreased slower after BD (4.5-fold ; median 5556.0 AU/mL) than after primovaccination (9.6-fold ; median 1038.5 AU/mL). Antibody titers before and one month after BD correlated weakly (r = 0.30) compared with a strong correlation (r = 0.65) between the corresponding post-primovaccination titers. Pre-vaccination COVID-19 had no effect on IgG levels after BD compared with a positive effect after primovaccination. Despite high post- booster IgG levels, 22.5% of participants contracted mild COVID-19. The trend of IgG decline indicates the need for further revaccination, but the vaccine type should be defined according to viral mutations.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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