Covishield dosage gap may be reduced for those aged 45 and above

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The Centre is set to reconsider the gap between two Covishield vaccine doses for those above 45 years of age, basis the increased availability of the vaccine, The Mint reported. The current gap between two doses of the vaccine is set at 12-16 weeks. Shortage of vaccines and supply constraints were the ostensible reasons for the longer gap. The National Technical Advisory Group on Immunisation in India (NTAGI) may take the final call in it’s meeting scheduled for next week.

“We have gathered data on the impact of vaccines and their dosage interval on different age groups and from different regions. In two to four weeks, we may decide on reducing dosage interval of Covishield, especially for those above 45 years and elderly based on final scientific evidence. Even a single dose of Covishield has shown a strong immune response in scientific studies,” Dr N K Arora, chairperson, covid-19 working group, NTAGI was quoted as saying in an interview.

While the government’s decision to keep a gap of 12-16 weeks between two doses was seen as a cover-up to compensate for vaccine shortage, the health ministry while quoting data from Serum Insitute of India (SII), the maker of the Oxford-AstraZeneca-developed vaccine, said that monthly Covishield vaccine production capacity is expected to be increased from 110 million doses per month to more than 120 million by the year end.

Previously in June, the Union health ministry had filed an affidavit before the Supreme Court stating its vaccine availability projection to 1.35 billion doses by the year-end. This projection was at 2.16 billion doses just a month ago.

“We do have enough doses and should cover the whole eligible population, but we don’t have spare doses. We will take a decision based on scientific evidence,” Arora said.

NTAGI had earlier recommended randomised vaccine trial of Covishield and other vaccines at varying time intervals.  It had also asked SII to study the effects of these varying gaps to gain better insight. India had begun with a four-week interval but later extended this gap first to 4-8 weeks and later to 12-14 weeks. Recently, the UK has also announced lowering the dosing interval to a maximum of two months.

“The minimum gap between two doses for any vaccine has to be four weeks while the maximum can go up to 8-12 weeks. This is based upon the efficacy and immune response of the vaccine as well. The ability of a vaccine to produce antibodies increases by 50% within this gap. Therefore, the second dose must be given only when there is enough scientific evidence proving production of anitibodies in the first dose,” said Dr DK Gupta, Infectious Diseases, General Paediatrics, Growth & Development expert at Felix Hospital, Noida.

Meanwhile, Dr. Chandrashekhar T., Chief Intensivist at Fortis Hiranandani Hospital in Navi Mumbai considered the probable decision of reducing the gap between two vaccines a good move.

“We do have evidence that highlights the immense response for the first dose itself beyond 4 weeks. Then if the person received the second dose at the gap of  6 weeks/8 weeks/ 12 weeks/ 16 weeks, the antibody response was subsequently better as the gap is more but considering the ongoing pandemic, it is also important to vaccinate considerable and significant population in this highly populated big nation,” he said.

If a particular disease is highly contagious, Dr Gupta stated, “The second dose can be given within a gap of four weeks. Otherwise, the gap can be extended till 12 weeks. However, multiple other factors impact this decision like pace of vaccine production, logistics and supply chain, etc.”

However, the government and ICMR have other responsibilities also i.e., to complete the vaccination process for the maximum population. It is important to fully vaccinate people with comorbidities.

“Remember we are expecting a third wave and before that, we need to vaccinate as many people as possible. Secondly, people with comorbidities need to be fully vaccinated soon, and thirdly, the vaccination process across the country needs to be completed so that we can open the economy,” Dr. Chandrashekhar T. concluded.

Meanwhile, India reported 44,643 new Covid-19 cases in the last 24 hours. With this, the active tally has climbed to 4,14,159 and constitutes 1.30% of total cases.