Population-wide study of COVID-19 vaccination shows that mix-and-match approach to booster vaccination offers the best protection

A new study on Chile’s national COVID-19 vaccination program, to be presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID 2022, Lisbon 23-26), and published in The Lancet Global Health, shows that giving a different type of vaccine (heterologous) for the third or ‘booster’ dose than was received for the first two doses, leads to better vaccine performance than using the same (homologous) inactivated SARS-CoV-2 vaccine for all three doses. The study is by Dr Rafael Araos, Institute of Science and Innovation in Medicine, Clinica Alemana, Universidad del Desarrollo, Dr Alejandro Jara, and Dr Eduardo A Undurraga from Pontificia Universidad Católica de Chile, and colleagues including Dr Johanna Acevedo from the Chilean Ministry of Health. The study assesses the effectiveness of CoronaVac (Sinovac Biotech), AZD1222 (Oxford-AstraZeneca), or BNT162b2 (Pfizer-BioNTech) vaccine boosters in individuals who had completed a primary two-dose immunisation schedule with CoronaVac, an inactivated SARS-CoV-2 vaccine which...