Can the first dose of the Covid-19 vaccine be given with one vaccine, the second with another? The first results of a study by British specialists of this mixing were obtained, published in a scientific article in The Lancet.
Let’s make a reservation right away – it’s safe. However, it increases the incidence of mild side effects. It is the lungs – low-grade fever, chills, fatigue, headache or muscle pain. At the same time, a mixture of Pfizer / BioNTech and Oxford / AstraZeneca preparations was investigated. The onset of mild symptoms was reported by the vaccinators themselves, one week after the second vaccination. The study involved 830 volunteers over 50 years of age.
Approximately one in three vaccinated people (34%), the first vaccination of which was given with the drug AstraZeneca, and the second with Pfizer, complained of a slight increase in temperature. The same side effect was observed in those who received the first Pfizer vaccine and the second AstraZeneca, that is, on the contrary, this turned out to be 41%. In volunteers who received 2 shots with the same drug, the occurrence of adverse reactions was observed less often – in 10% after two doses of AstraZeneca and 21% after Pfizer. Matthew Snape, Lead Investigator and Associate Professor in the Department of Pediatrics and Vaccines at Oxford, notes:
“These reactions are expected in vaccines and are more or less the same. It is important to inform people about these results, especially as several countries are considering such mixed dosing regimens. The results of the study show that mixing doses can lead to an increase in the number of absenteeism to work the day after vaccination, which should be taken into account, especially when planning vaccinations of health care workers. Importantly, there are no safety concerns, and we do not yet know if this will affect the immune response. We hope to present this data in the coming months, maybe in June. “
The Com-CoV study, which began in February, was continued in April and expanded to include other vaccines (Moderna and Novavax) to test 1,050 volunteers. Various options are being considered, including the first dose from Pfizer or AstraZeneca and the second from Moderna or Novavax. The effect of a combination of doses of different drugs on immunity remains unknown, as data from the same state-funded Com-CoV study are pending.