Low clinical utility of testing for anti-platelet factor 4 in asymptomatic individuals after ChAdOx1 nCoV-19 vaccine.
Int J Lab Hematol
; 44(2): 424-429, 2022 Apr.
Article
em En
| MEDLINE
| ID: mdl-34850575
ABSTRACT
INTRODUCTION:
The development of anti-platelet factor 4 (PF4) antibodies is linked to a rare thrombotic complication described now as vaccine-induced immune thrombotic thrombocytopenia (VITT). This clinical syndrome with thrombosis and thrombocytopenia was reported after exposure to the Oxford-AstraZeneca COVID-19 vaccine, ChAdOx1 nCoV-19 vaccine (AZD1222), and Ad26.COV2.S vaccine (Janssen/Johnson & Johnson). In the absence of the clinical features, the incidence of positive anti-PF4 antibodies in asymptomatic individuals post-vaccination is unclear.METHODS:
The aim of this study was to evaluate the development of anti-PF4 antibodies in asymptomatic individuals 14-21 days after receiving the first dose of ChAdOx1 nCoV-19 vaccine (AZD1222) and BNT162b2 vaccine. Prospectively, we collected serum from individuals before and after ChAdOx1 nCoV-19 vaccine and BNT162b2 vaccine and measured anti-PF4 antibodies using the Asserachrom HPIA IgG ELISA (Stago, Asnieres, France).RESULTS:
We detected positive anti-PF4 antibodies in 5 of 94 asymptomatic individuals post-vaccine with a rate of 5.3% with low titers (OD 0.3-0.7). Four of 5 individuals who tested positive after the vaccine had also positive anti-PF4 antibodies before the vaccine, which indicates that a majority of the positive results are due to preexisting anti-PF4 antibodies. We did not find a relation between the development of anti-PF4 antibodies and the immune response to the vaccine, status of prior COVID-19 infection, and baseline characteristics of participants. None of the participants developed thrombosis nor thrombocytopenia.CONCLUSION:
Our results provide new evidence to guide the diagnostic algorithm of suspected cases of VITT. In the absence of thrombosis and thrombocytopenia, there is a low utility of testing for anti-PF4 antibodies.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Vacinas
/
COVID-19
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Revista:
Int J Lab Hematol
Assunto da revista:
HEMATOLOGIA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Arábia Saudita