Combined Hormonal Contraception and the Adenoviral Vector Covid-19 Vaccines

Abstract

There are at least 4 different types of covid-19 vaccines that are available worldwide. The most widely used ones are the mRNA genetic vaccine and the viral vector vaccine. In the midst of the COVID-19 pandemic and after the administration of millions of those vaccines globally over few months, several national health authorities across Europe decided to pause the administration of the chimpanzee adenovirus-vectored vaccine1 (ChAdOx1nCoV-19, AZD1222; Oxford/AstraZeneca) after sporadic reports of severe cases of thrombocytopenia, bleeding, or thrombosis in those who received this vaccine. This complication has been identified as Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT) that affects mostly woman under the age of 55 years at a rate of 1:100,000 vaccine doses. Combined hormonal contraceptives (CHC) are known to carry the risk of thrombosis in certain high-risk population. Accordingly, women taking those contraceptives raised their concern of getting such vaccine. This review will attempt to explain the different mechanisms of thrombosis which abolish any link between the VITT complication and the use of CHC. Reassuring statements from authoritative agencies are also included.