India on January 16, 2021, rolled out the world’s largest COVID-19 vaccination drive against coronavirus infection. So far, the country has administered more than 24 crore doses. In the past 24 hours, more than 33.7 lakh vaccine doses were administered.
India is currently administering doses of COVAXIN, COVISHIELD, and Sputnik V. However, vaccinating people with different vaccines is yet to be approved.
The country is investigating if people can be administered different COVID-19 vaccines. Using different vaccines would mean immunizing people with one dose of a particular vaccine brand followed by a second dose of another vaccine brand.
The Indian government is expecting that the country will have a total of up to eight COVID-19 vaccines by December 2021. All these vaccines would be produced using mRNA, viral vector, recombinant protein, and DNA technologies. With these vaccines, India stands a chance to conduct trials on combinations of vaccines that have not been tested till now globally.
The eight COVID-19 vaccines in India would be COVISHIELD, COVAXIN, Sputnik V, Novavax’s COVOVAX, Bharat BioTech’s Nasal Vaccine, Biological E Limited's Covid-19 subunit vaccine, Zydus Cadila’s DNA vaccine ZyCoV-D, and Gennova’s mRNA vaccine.
Are other countries mixing doses of COVID-19 vaccines?
• Several countries are mixing doses of COVID-19 vaccines. The European Union (EU), the United Kingdom (UK), Canada are countries that are offering Moderna or Pfizer as alternatives to AstraZeneca. South Korea and Spain are also planning to mix vaccines.
• China and Russia are also deliberating upon mixing vaccines. Russia is looking into mixing Sputnik V and AstraZeneca vaccines.
• The Centers for Disease Control in the US carried out mixing of both its mRNA vaccines – Moderna and Pfizer under exceptional circumstances.
• The Com-COV trials in the UK are examining mixing Novavax and Moderna vaccines. The results of the experiment would be out by August 2021.
Any there benefits of mixing COVID-19 vaccines?
There have been several benefits noted regarding the mixing of COVID-19 vaccines.
• Mixing of vaccines helps in completing the entire course of vaccination with full safety. Several countries such as Canada, the UK, France had to discontinue AstraZeneca due to emerging cases of rare blood clots after immunization.
• Mixing of vaccine doses also helps in countering the issue of shortage or unavailability of a particular vaccine dose brand. People need not come in again and again to vaccination centers to get the second dose of the same vaccine, health experts noted.
• Health experts also note that the mixing of vaccine doses enables our immune system in generating a better response at fighting the infection, especially mutants and variants. Certain vaccines are effective against certain mutants, particularly in the case of AstraZeneca and COVISHIELD.
Is mixing COVID-19 vaccines dangerous?
The health experts say our immune system can adapt and fight a lot against infections. However, the health community does have few concerns about mixing COVID-19 vaccines.
Currently, the health experts are concerned about:
• Safety of mixing vaccines: There are more detailed studies going on around the world to assess the combinations and concerns of mixing vaccines. The researchers are investigating the sequence of vaccines, in case of mixing, that should be administered for a better immune response.
• Combinations of vaccines: There are studies being conducted to assess the combinations of different vaccines. This would give detailed insight into which pair of vaccines generate a wider immune response and which can have severe side effects. There are studies that show a combination of Pfizer and AstraZeneca may have more side effects.
• Other complexities: The Coalition for Epidemic Preparedness Innovations has cited few possibilities of complexities in the case of mixing COVID-19 vaccines owing to the differences in the storage conditions, the shelf life of different vaccines, efficacy levels, etc.