Anti-spike S1 IgA, anti-spike trimeric IgG, and anti-spike RBD IgG response after BNT162b2 COVID-19 mRNA vaccination in healthcare workers

Most studies on immune response after coronavirus disease 2019 (COVID-19) vaccination focused on serum IgG antibodies and cell-mediated immunity, discounting the role of anti-SARS-CoV-2 neutralizing IgA antibodies in preventing viral infection. This study was aimed to quantify serum IgG and IgA neutralizing antibodies after mRNA COVID-19 vaccination in baseline SARS-CoV-2 seronegative healthcare workers.The study population consisted of 181 SARSCoV-2 seronegative healthcare workers (median age 42 years, 59.7% women), receiving two doses of Pfizer COVID-19 vaccine BNT162b2 (Comirnaty). Serum samples were collected before receiving the first vaccine dose, 21 days (before the second vaccine dose) and 50 days afterwards. We then measured anti-spike trimeric IgG (Liaison XL, DiaSorin), anti-spike receptor binding domain (RBD) IgG (Access 2, Beckman Coulter) and anti-spike S1 subunit IgA (ELISA, Euroimmun). Results were presented as median and interquartile range (IQR).Vaccine administration elicited all anti-SARS-CoV2 antibodies measured. Thirty days after the second vaccine dose, 100% positivization occurred for anti-spike trimeric IgG and anti-spike RBD IgG, whilst 1.7% subjects remained anti-spike S1 IgA negative. The overall increase of antibodies level ratio over baseline after the second vaccine dose was 576.1 (IQR, 360.7-867.8) for anti-spike trimeric IgG, 1426.0 (IQR, 742.0-2698.6) for anti-spike RBD IgG, and 20.2 (IQR, 12.5-32.1) for anti-spike S1 IgA. Significant inverse association was found between age and overall increase of anti-spike trimeric IgG (r=-0.24; p=0.001) and anti-spike S1 IgA (r=-0.16; p=0.028), but not with anti-spike RBD IgG (r=-0.05; p=0.497).mRNA COVID-19 vaccination elicits sustained serum levels of anti-spike trimeric IgG and anti-spike RBD IgG, while also modestly but significantly increasing those of anti-spike S1 IgA.Većina studija imunog odgovora nakon oboljenja korona virusom (COVID-19) i vakcinacije zasniva se na serumskim IgG antitelima i ćelijski posredovanom imunitetu, ne vodeći računa o anti-SARS-CoV-2 neutralizujućim IgA antitelima i sprečavanju virusne infekcije. Ovo izučavanje ima za cilj da kvantifikuje serumski IgG i IgA neutralizujućih antitela nakon mRNA COVID-19 vakcinacije kod SARSCOV-2 seronegativnih zdravstvenih radnika.Populaciju za izučavanje činilo je 181 SARS-COV-2 seronegativna zdravstvena radnika (oko 42 godine starosti, 59,76% su bile `ene) koji su primili dve doze Pfizer COVID10 vakcinu BNT162b2 (Comirnaty). Uzorci seruma su uzeti pre prijema prve vakcine, 21 dan pre druge doze vakcine i 50 dana nakon druge doze vakcine. Mereni su anti-spike trimerik IgG (Liaison XL, DiaSorin), anti-spike receptor vezujući domen (RBD), IgG (Access 2, Beckman Cooulter) i antispike S1 subjedinica IgA (ELISA, Euroimmun). Rezultati su prikazani kako medijana i interkvartilna oblast (IQR).Vakcina je proizvela sva anti-SARS-CoV-2 antitela koja su merena. Trideset dana nakon davanja doze vakcine javila se 100% pozitivnost na anti-spike trimerni IGG i antispike RBS IgG, dok je 1,7% osoba bilo negativno na antispike S1 IgA. Ukupno povećanje nivoa antitela iznad bazične granice nakon druge vakcine bila je 576,1 (IQR, 360,7-867,8) za anti-spike trimerni IgG, 1426,0 (IQR, 742,0-2698,6) za anti-spike RBS IgG i 290,2 (IQR, 12,5-32,1) za anti-spike S1 IgA. Značajno obrnuta povezanost je nađena između godina i i ukupnog povećanja anti-spike trimernog IgG (r = -0,24; p = 0,001) i anti-spike S1 IgA (r = 0,16; p = -0,028) ali ne i sa anti-spike RBD IgG (r= 0,05; p = 0,497).mRNA COVID-19 vakcinacija dovodi do povećanja nivoa u serumu anti-spike trimernog IgA i RBD IgG, kao i do značajnog povećanja u serumu anti-spike S1 IgA.