Several countries have embraced the idea of using distinct COVID-19 vaccines for the first and second doses. But a death in Korea is fueling concerns about the strategy, and some public authorities have warned against the practice.
Canada, Korea, Thailand and Germany have authorized the use of a heterologous prime-boost COVID-19 vaccination strategy to manage supply constraints.
A police officer in South Korea, however, has died after receiving first an AstraZeneca vaccine dose followed by a Pfizer dose, according to The Korea Times. Health authorities there will investigate the death of the 52-year-old officer, who passed away three days after receiving his second vaccine dose.
A recent preprint study published in The Lancet suggested that combinations of AstraZeneca and Pfizer vaccines were effective. Data, however, are preliminary.
Germany, Canada and Thailand have recommended heterologous vaccinations to their citizens. German Chancellor Angela Merkel herself received an AstraZeneca dose and, subsequently, one from Moderna.
European Medicines Agency guidelines also acknowledged that “experts responsible for the vaccination programmes in over half of Member States have decided, with a view to their national situations, to use different vaccines for the second dose from the ones used for the first dose.”
The statement adds that data from Germany, UK and Spain suggest that the strategy is safe and effective.
CDC, however, has not embraced the idea, given the considerable supplies of vaccines in the country.
U.S. officials have also concluded that it will not consider people receiving distinct COVID-19 vaccines as fully vaccinated.
The WHO has also not supported the concept. Last week, the organization’s chief scientist Dr. Soumya Swaminathan cautioned against individuals mixing and matching COVID-19 vaccines without the support of public health authorities. “We are in a data-free, evidence-free zone as far as mix-and-match [is concerned],” Swaminathan said. “There is limited data on mix-and-match.”
Filed Under: Infectious Disease