Should India Increase Covishield Dose Spread After Lancet Study? – Quartz India

The science of vaccines is constantly evolving, and a new study could change when someone receives their second dose of the Covid-19 vaccine.

The Oxford-AstraZeneca vaccine, made in India by the Serum Institute of India and sold as Covishield, has shown greater effectiveness when the second dose is given after an interval of 12 weeks, according to a study published by the medical journal Lancet March 6. Currently, Indians who are vaccinated at Covishield must receive their second booster dose after four weeks.

The study, based on the results of more than 17,000 trial participants, found that the efficacy of the AstraZeneca vaccine increased from an average of 55.1% when two standard doses are given to an interval of less than six weeks to 81.3% when the interval is at least 12 weeks.

It also revealed that those who received two standard doses of the vaccine had an average 63.1% resistance to symptomatic Covid-19. This number increased significantly to 80.7% in participants who received a half dose first, followed by a second full dose.

This could mean that the Covishield vaccine is at its least potential effectiveness due to the dosing regimen in India.

The different dosing scenarios

The conversation around a difference in dosage size first emerged as a trial anomaly during the Oxford-AstraZeneca Phase 3 trials. Since then, the Swedish pharmaceutical company has been studying the benefits of various dosage regimens.

The Lancet study also found strong evidence in favor of a ‘longer interval vaccination strategy’, which was first adopted by the UK government amid much criticism.

The UK had recommended a long interval for AstraZeneca and Pfizer Covid-19 vaccines in January. This worried the medical community because Pfizer had not conducted any trial studies to determine whether a longer gap would make its vaccine more effective. The doctors then asked for an “emergency review” of this decision.

But later, in February, a World Health Organization (WHO) panel supported the 12-week interval, based on the higher immunogenicity and efficacy benefits that accompanied a longer gap.

Two days after the WHO group’s recommendation, India’s expert group on vaccinations met on February 13 to discuss possible scenarios.

But India chose to stick to the original plan. “For now, the current recommendation (to start vaccinating after 28 days) is valid,” Vinod K Paul, chairman of the national expert group on the administration of vaccines for Covid-19, told The Times newspaper. of India.

Stick to a four week interval

India has often been criticized for not keeping up with the rapidly evolving science of different Covid-19 treatment plans and for having protocols in place that do not change quickly with new information.

Currently, for example, beneficiaries who receive either the Covishield vaccine or the Covaxin vaccine, produced in India, are automatically scheduled to receive their second dose after four weeks. The Government of India’s Co-WIN Platform for Immunization Program does not allow registered users to choose a longer interval.

One reason for India’s reluctance to adopt a 12-week interval plan for its vaccination campaign could be that Covishield’s transition studies in India did not include dosing variables. As such, the emergency approval for Covishield is based on data it has collected from its local trials in India.

Another possible factor could be the logistical aspect of vaccinating 300 million people by August, a target the Indian government has set for itself. Yesterday (March 9), nearly 20 million people received the first dose of the Covid-19 vaccine, and just over 4 million also took the second dose.