Doctors from the city have welcomed the Indian Council of Medical Research (ICMR) study of the Covishield-Covaxin mix that offers better immune protection. Also, it was found that the adverse effects were not different from the same vaccine regimen.
However, experts believe that the trial is still in the early stage. Moreover, if both vaccines are available simultaneously, the same vaccine must be used for both the first and second dose, considering very high vaccine efficacy (94% to 95%). Dr. Sunil Jain, head of emergency medicine, Jaslok Hospital & Research Centre, said immunisation with a combination of two vaccines, Covishield and Covaxin, was not only safe, but also showed better immunogenicity.
“Mixing vaccines could develop a wider and broad-range response against different variants and mutations of the virus. The presence of neutralizing antibodies rose sevenfold after people who already received the first shot of Covishield were given Covaxin. Higer doubling rate was observed after the second Covishield shot,” said Dr. Jain.
He further added that mixing the vaccines may increase frequency of mild side-effects. But these symptoms were short-lived and there was no hospitalizations or other concerns. “There are concerns of reports of rare blood clots linked with the Covishield vaccine. Mixing and matching allows the completion of immunization while ensuring safety. Evidence suggests that such mixing has a good safety profile,” said Dr. Jain.
Dr Rahul Tambe, senior consultant, Internal Medicine and Infectious Diseases, said, “In the next phase, we will need to widen the scope of the study and monitor how individuals with varied immunological profiles react to the vaccine combination.”
Dr Lancelot Pinto, Consultant Pulmonologist, P.D Hinduja Hospital & MRC said, “The heterologous prime-boost strategy has been used for vaccines before, and it does not come as a surprise that two vaccines stimulating antibodies targeted towards different parts of the virion produce a more robust immune response.”
