Mixing Covid-19 vaccines may lead to increased symptoms, study suggests

Mixing coronavirus vaccines increased the frequency of mild to moderate symptoms in those who received different jabs for the first and second dose, preliminary data suggests. The Com-Cov study was launched in February to investigate alternating doses of the Oxford/AstraZeneca and Pfizer Covid-19 jabs, with either being given as the first dose, and then the other as the second.