Several medical studies are underway to test the efficacy of switching Covid-19 vaccines. A mixed program, in which one injection of the Pfizer vaccine is given after one injection of AstraZeneca, produced more antibodies than two injections of AstraZeneca, according to an Oxford study on June 28.
The following are countries that are considering, or have decided to adopt, such a solution:
* Bahrain said on June 4 that eligible candidates could receive a booster injection of the Pfizer / BioNTech or Sinopharm vaccine, regardless of the injection they initially received.
* The country’s National Advisory Committee on Immunization said on June 17 that provinces should offer recipients of a first dose of AstraZeneca vaccine a different injection for their second dose, CBC News reported.
The committee had said earlier this month that people injected for the first time with an AstraZeneca injection could choose to receive a different vaccine for their second dose.
* The Italian medicine agency AIFA said on June 14 that people under the age of 60 who were inoculated with a first dose of AstraZeneca may receive a different second injection.
* Russia may start trials with a Covid-19 vaccine combining its Sputnik V vaccine and various Chinese injections in Arab countries, the Interfax news agency said, citing Russia’s RDIF sovereign wealth fund on June 4.
The RDIF also said that no negative side effects were found during clinical trials combining the Covid-19 vaccine with AstraZeneca and Sputnik V injections, Interfax reported.
* South Korea said on June 18 that some 760,000 people who were inoculated with a first dose of AstraZeneca will receive the Pfizer jab as a second injection due to delays in shipping through the global COVAX vaccine exchange scheme.
* Health Minister Carolina Darias said on May 19 that Spain would allow people under the age of 60 who received an AstraZeneca injection first to receive a second dose of the AstraZeneca or Pfizer vaccine, after preliminary results of a study conducted by the Carlos III Health Institute, backed by the state.
United Arab Emirates
* The United Arab Emirates has made the Pfizer / BioNTech coronavirus vaccine available as a booster shot for those initially immunized with a vaccine developed by the China National Pharmaceutical Group (Sinopharm).
A representative for Mubadala Health, part of the state fund, said that a different vaccine could be provided as a booster shot, but this was at the discretion of the recipient and health professionals made no recommendations.
* Novavax said on May 21 that it would participate in a mixed vaccine trial starting in June in the UK to test the use of an additional dose of vaccine from a different producer as a booster.
* The US National Institutes of Health (NIH) said on June 1 that they had begun a clinical trial in fully vaccinated adults to evaluate the safety and immunogenicity of a booster shot of a different vaccine.