Six different Covid-19 vaccine booster shots are safe and build a strong immune response in people who have had two doses of the AstraZeneca or Pfizer vaccines, according to a new study.
The United Kingdom-based study published in The Lancet assessed immune response rather than protection against infection or severe disease.
The study enrolled 2 878 adults aged 30 years and older who were fully vaccinated with either the Pfizer or AstraZeneca shots. The participants were divided into groups. The first group received Novavax; half a dose of the Novavax and AstraZeneca; or the quadrivalent meningococcal conjugate vaccine (MenACWY).