Pune . A good news has come to the fore regarding the mixture of two important vaccines used against Covid-19 in India, Covishield and Covaxin. According to a study by ICMR, this mixture is also safe and also provides better immunity. Both these vaccines are prepared on separate platforms like Covidshield is prepared on the adenovirus vector platform, whereas the vaccine is made through inactivated virus in Covaxin. Studies are going on around the world whether two doses of the same vaccine are more effective or a mixture of different vaccines shows a better effect.
Experts caution that there is still limited study on the use of a mixture of two different vaccines. It would not be right to say anything about the use of the mixture right now. It is also important to know that two different vaccines should not be given at once, otherwise the results may be opposite.
The idea for this study came from a mistake, in fact, in May, 18 villagers in Uttar Pradesh were accidentally given a dose of Covaxin, six weeks after being exposed to a coveshield. Comparative study of these 18 villagers was done with 40 people who got Covashield and 40 people who were given Covaxin. The study has revealed that while the vaccine made on the adenovirus vector platform and the vaccine prepared from the inactivated virus is safe, it also exhibits better immunity than two doses of the same vaccine. However, this study is yet to be reviewed.
Study of preliminary data is a notable step but
According to the news published in the Indian Express, immunologist Dr. Vinita Bal says that ICMR’s study of preliminary data of people who accidentally got two vaccines is a remarkable step. But it is too early to say anything on this, the results from this study are preliminary. And this result has come on the basis of the mix taken by only 18 people. At present, it is difficult to make any immunity-related statement on this. However, this data suggests that a mixture of different vaccine doses shows better results than two doses of the same vaccine. Other experts also believe that in principle, even though we can say something about it, but it is difficult to say anything on whether the mixture is better than two doses of the same vaccine.
So should the vaccine mix be applied?
According to the World Health Organization, limited data is currently available regarding the mixture of vaccines. However, AstraZeneca has proposed that the mRNA vaccine (Pfizer or Moderna) can be used as a second dose. The company says that if the second dose is not available after the first dose of AstraZeneca vaccine, then mRNA can be used as a second dose. The company has given this proposal based on the principle of how the vaccine works. Experts say that drug regulators only know as much as the company has researched them, and that no studies have been reported of a mix of the two vaccines as the company is trying to mix with another company. Wants to sell both her own doses. If it is studied at the academic level, then it will require a long time and a large estimate cannot be made from limited information.
When to mix vaccine
Even before Covid-19, better results have been seen in the study of mixtures of other vaccines. Vaccine platforms may vary depending on their antibody and T-cell response potential. Experts say that if one platform induces an antibody response, the other could be a platform to induce a T-cell response (eg vectors and a DNA vaccine). This policy is generally used on vector based platforms. Two different vaccine policies have been studied in the past on HIV, Malaria, Flavivirus (Dengue), HPV, Ebola and Influenza. In the case of Covid-19, the policy of two different vaccines can give better results and its second advantage will also be that if it is successful, then there will be a flexibility regarding the vaccine and this will lead to the vaccine being seen continuously in the country. Deficiency can also be controlled.
Can a combination of Covishield and Covaxin work?
ICMR data suggests that the two different vaccines may increase anti-A protein due to the boost of Covaxin, although more data will be needed to know how effective the combination of CovaShield and Covaxin is. The mixture was not approved yet because no clinical trials have been conducted on it. Experts say that the vaccine made on any such platform cannot be mixed. Rather, many facts should be considered about it, such as how much is related to immunity, which vaccine gives what kind of immune response. What would be the correct sequence to increase the response, what should be the interval between the two doses. How long is immunity?
Where did it start
The idea of applying different vaccines initially came out of Europe, when some people complained of blood clotting after the AstraZeneca vaccine, then a second dose of the vaccine made on a different platform was proposed, for youth in many countries. The motion was passed.