Home >Science >Health >Recommend random trials of varying dose intervals for vaccines: NTAGI

After much criticism over increasing the vaccine dosage interval from 4-6 weeks to 12-16 weeks in India, the National Technical Advisory Group on Immunization (NTAGI) in India has recommended a randomized trial of varying dosage intervals for all covid-19 vaccines, including Covishield.

In a meeting of the NTAGI, authorities said a national vaccine tracking platform must be established to determine the impact of covid vaccines and track breakthrough infections, which are detected two weeks after getting the second dose or full schedule of the vaccine.

“Indian Council of Medical Research (ICMR) is currently doing harmonization works for different administrative data, including RT-PCR data, disease data and genomic surveillance data. If these are all harmonized, that would give a very close look at what is happening on the ground on a real time basis," the minutes of the NTAGI meeting read.

“It is recommended that a randomized trial of varying dose interval of Covishield and other vaccines as they come in should be planned and immediately embedded in the proposed study, and the manufacturer should be asked to do the study," it added.

India’s decision to change the dosage interval was based largely on studies conducted in the UK. The two largest consumers of Covishield are India and the UK, which was using a dose interval of three months until recently before reducing to two months for the 50-plus age group. “Real-world data from UK showed 65% to 88% protection rate after the first dose, if the interval is up to 12 weeks. Therefore, based on real-world evidence, dosage intervals between two doses of Covishield was increased from 4-8 weeks to 12-16 weeks. No change in dosage interval of Covaxin was recommended. Interval of 3-6 weeks between two doses of Sputnik V vaccine is recommended," according to the minutes of the meeting.

Canada has recommended four months’ interval, while Sri Lanka (2.5 months), Bangladesh (2-3 months) and Spain (4 months) have set their respective arrangements. The European Medicines Agency (EMA) has recommended 1-3 months interval for the vaccine, while the World Health Organization has recommended 2-3 months interval between two doses of Covishield. India had started with a four-week interval, but later extended it to 4-8 weeks based on available evidence, the government had said.

N.K. Arora, chairperson of the working group of immunisation advisory body NTAGI, had earlier said that India will revisit the dosage interval for Covishield and take appropriate action based on emerging data.

“Covid-19 and vaccination are very dynamic. Tomorrow, if the vaccine platform tells us that a narrower interval is better for our people, even if the benefit is 5-10%, the committee will take the decision on the basis of merit. On the other hand, if it turns out that the current decision is fine, we will continue with it," he had said.

In April, data released by the UK’s Public Health England, showed vaccine efficacy varied between 65% and 88% when the interval was 12 weeks.

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