Data from Brazil’s Health Ministry shows that at least 16,500 people have taken different vaccines for their first and second jabs. The mix-up happened between the AstraZeneca and CoronaVac vaccines — the two being rolled out in Brazil so far — and mainly affected health workers.
Because there are still no studies testifying the effectiveness of using different vaccines, it is unclear how much protection — if any — this approach offers. We still can’t account for possible adverse reactions caused by the mix-up.
These two vaccines also have different standards and employ different technologies to generate immunity: the AstraZeneca vaccine is based on the virus’s genetic instructions for building the spike protein and uses double-stranded DNA. Meanwhile, the CoronaVac works by teaching the immune system to make antibodies against the SARS-CoV-2 coronavirus. These antibodies then attach themselves to viral proteins, such as the so-called spike proteins that stud its surface.