The more people vaccinated against coronavirus in the world, the more various questions arise about the drugs themselves.
Some countries purchase vaccines from different manufacturers, but what if suddenly there is not enough vaccine from one manufacturer for a patient for a second dose?
When the manufacturer is different, but the vaccine is the same
All AstraZeneca COVID-19 vaccines, regardless of country of origin, are interchangeable, according to the Ministry of Health. The relevant recommendations to the Ministry of Health were provided by the National Technical Group of Experts on Immunoprophylaxis (NTGEI).
"AstraZeneca vaccine (AZD1222) manufactured by the Serum Institute of India (CoviShield) and a vaccine manufactured by the South Korean company SK Bioscience Co Ltd. (AstraZeneca-SKBio) are identical in composition and manufacturing technology. They are not considered as different vaccines and are interchangeable, the NTGEI explained," the statement says.
Indian-made AstraZeneca was named CoviShield. On March 25, 2021, the AstraZeneca vaccine officially changed its name to Vaxzevria. This happened due to the rejection to use the vaccine because of thrombosis and blood clotting disorders cases in people vaccinated with CoviShield. Changing the name will not change the product itself, but the packaging may change.
When both the manufacturer and the vaccine are different
According to the Ministry of Health, different types of vaccines produced by different companies are not interchangeable.
"That is, people who were inoculated with the first dose of the vector vaccine AstraZeneca/CoviShield cannot be inoculated with a second dose of a different type of vaccine, for example, the mRNA vaccine from Pfizer-Biontech or the inactivated vaccine CoronaVac/Sinovac—there is not enough data on interchangeability for these drugs, and they may differ in manufacturing technologies," the Ministry stated.
However, in the UK, the United Kingdom's National Health Service has allowed various vaccines against coronavirus in some cases.
The country's government stated that a combination of two different vaccines against COVID-19 can be given if, for example, a second dose of the same vaccine is not available. In the UK, it is considered better to introduce a different vaccine than to delay the reinoculation.
The US Centers for Disease Control and Prevention (CDC) has also authorized the first inoculation against coronavirus with one vaccine and the second dose with another. CDC has added that vaccines approved in the United States are not interchangeable, but in some cases any available mRNA COVID-19 vaccine can be used for the second dose.
Different vaccines—is it safe?
According to virologist John Moore, British officials "have turned their backs on science and are just trying to figure out a way out of this mess."
There is currently no evidence of the immunity level that a person who has mixed the vaccines will have. The US Centers for Disease Control and Prevention emphasized that coronavirus vaccines are not interchangeable and the safety and efficacy of the mixed product series has not been estimated.
A Pfizer spokesman did not rule out the possibility of mixing vaccines, but the company is confident that the implementation of such a decision must be carefully monitored.