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Hospitals see rise in enquiries on mixing vax

Hospitals see rise in enquiries on mixing vax

MUMBAI : Several individuals who have received one shot of Covaxin have inquired whether they can get Covishield for their second shot, and have also shown interest in getting booster shots, healthcare providers said. However, lack of studies and data from the Indian Council of Medical Research (ICMR) on mixing doses or giving booster shots means that hospitals cannot meet these requests, especially since the government has not issued any guidelines in this respect. The lack of World Health Organization’s emergency use listing (EUL) for Covaxin means those who have received the jabs are still not considered “vaccinated by countries that are opening up travel for fully vaccinated individuals, i.e., those who have taken two shots of a WHO-approved vaccine. In India, only Covishield is approved by the WHO, and it is considered valid vaccine proof by several countries such as US, Europe and Canada. “We have been getting several enquiries on mixing doses, but we can’t technically advise about it, as we still don’t know if it is scientifically safe, said Dr. Hiren Ambegaonkar, CEO of Surya Hospital, in Mumbai. “Till we get a proper guideline from the government, we cannot administer these doses. Earlier this month, the US Food and Drug Administration authorized the mixing of Moderna’s mRNA vaccine and Johnson and Johnson’s adenovirus vaccines, after studies showed better immune response for such mixing. A study in Canada’s Quebec showed mixing of AstraZeneca and Pfizer doses also provided better immune response. However, in case of India, limited study on mixing doses has led to ambiguity on effectiveness of such a move. “Mixing of vaccines has generally shown to result in a more robust immune response, as compared to giving the same vaccine twice, as shown in multiple studies. However, only results of a small study of mixing Covaxin and Covisheild in 18 people is available from Uttar Pradesh, where a different second dose was given by mistake, a healthcare professional said on condition of anonymity, adding results from a study in a large group of subjects is still awaited. ICMR is responsible for conducting studies on vaccine effectiveness and mixing doses. Christian Medical College at Vellore is conducting a study on 1,100 participants on mixed vaccine doses, which is expected to last at least six months. “There would be significant advantages to having flexible immunization programmes where the second vaccine dose is not necessarily the same as the first dose and the intervals between the doses are similar. Accordingly, this study will determine the safety as well as the immune responses to mixed administration of Covishield following Covaxin and vice-versa given at an interval of 56+/- 7 days and make comparisons with the same 2 dose administration of these two vaccines, according to the trial document of CMC, Vellore that Mint has viewed. The document explains that safety and immune responses will also be determined following the mixed booster dose administration of available vaccines (after an interval of 3-6 months after the 2nd dose) including Covishield and Covaxin following same and mixed prime vaccination with Covishield or Covaxin Download.

science 2021-10-28 Livemint