As Covid-19 infections continue to rise unabated in India, the government has announced the opening of vaccination for people above the age of 45 from April 1. Meanwhile, on experts’ advice, the interval between the first and second doses of Covishield was increased to up to eight weeks in its ongoing vaccination drive against the novel coronavirus. The vaccine is Serum Institute of India's version of AZD1222 – Developed by AstraZeneca in collaboration with the University of Oxford.
What is the optimal time interval between the required two doses?
The time interval between two doses of the Covishield vaccine has been extended from four-six weeks to four-eight weeks, while the second dose of Covaxin can be taken four to six weeks after the first dosage. The government has advised people to take the second dose of Covishield between six and eight weeks after the first and protection from the virus would be optimum. However, a delay beyond the eighth week may leave the beneficiary vulnerable.
Why has the government increased the interval between doses?
On the recommendation of two expert groups– the National Technical Advisory Group on Immunisation (NTAGI) and National Expert Group on Vaccine Administration for Covid-19 (NEGVAC), the Ministry of Health and Family Welfare concluded that the protection that it provides against Covid-19 is enhanced if the second dose is administered between 6-8 weeks.
Do studies support the idea of increasing the interval?
As per the Interim results from phase 3 clinical trials conducted on 32,000 participants across the US, Chile and Peru show that the vaccine had an efficacy of 79 per cent against symptomatic Covid-19 when the interval between doses was four weeks, Oxford University and AstraZeneca suggested. Significantly, the efficacy in the cases of severe or critical symptomatic Covid-19 cases was 100 per cent.
Who is eligible for vaccination in the third phase?
In this third phase of vaccination, starting April 1, everybody over the age of 45 will be eligible for the vaccination. The cut-off date has been set as January 1, 1977, hence one must be born before this date to be able to receive the covid jab. Earlier the government had a clause of comorbidities for inoculation which has now been removed.
What happens after you get the second dose of the vaccine?
The government advises those getting inoculated to collect their vaccination certificate after receiving the vaccine shot. This certificate can be procured digitally or as a form of a hard copy but collecting this has been touted as significant by the government.