In the present study, immunogenicity data in 61 vaccinated healthcare workers (HCWs) either infection naïve (naïve HCWs) or with infection of Delta and/or Omicron COVID-19 (experienced HCWs) were evaluated up to 270 days after the second dose of BNT162b2 vaccine and up to 90 days after a booster dose. A decrease in antibody levels at 270 days following administration of the second dose (p = 0.0335) was observed, although values did not fall below the positivity threshold (33.8 BAU/ml). After booster vaccination, antibody levels increased after 30 days (p = 0.0486), with much higher values than after first and second vaccination. Antibody levels then decreased at 60 and 90 days after the booster dose. A comparison between mean antibody levels of naïve and experienced HCWs revealed higher values in experienced HCWs, resulting from both natural and vaccination-induced immunity. A total of 14.7% of HCWs contracted the Omicron virus variant after the vaccine booster, although none showed severe symptoms. These results support that a booster dose results in a marked increase in antibody response that subsequently decreases over time.

Antibody levels after BNT162b2 vaccine booster and SARS-CoV-2 Omicron infection

Vietri, Maria Teresa;Passariello, Luana;Albanese, Luisa;Maria Molinari, Anna;Francesco Angelillo, Italo
2022

Abstract

In the present study, immunogenicity data in 61 vaccinated healthcare workers (HCWs) either infection naïve (naïve HCWs) or with infection of Delta and/or Omicron COVID-19 (experienced HCWs) were evaluated up to 270 days after the second dose of BNT162b2 vaccine and up to 90 days after a booster dose. A decrease in antibody levels at 270 days following administration of the second dose (p = 0.0335) was observed, although values did not fall below the positivity threshold (33.8 BAU/ml). After booster vaccination, antibody levels increased after 30 days (p = 0.0486), with much higher values than after first and second vaccination. Antibody levels then decreased at 60 and 90 days after the booster dose. A comparison between mean antibody levels of naïve and experienced HCWs revealed higher values in experienced HCWs, resulting from both natural and vaccination-induced immunity. A total of 14.7% of HCWs contracted the Omicron virus variant after the vaccine booster, although none showed severe symptoms. These results support that a booster dose results in a marked increase in antibody response that subsequently decreases over time.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11591/477549
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