- It is perplexing to note why and how the Government of India concluded that increasing the gap between two doses of Serum Institute of India manufactured Covishield would be beneficial to the citizens. As you are aware, the gap was increased from the earlier 4-6 weeks to 12-16 weeks between the two doses bang in the middle of the raging second Covid wave in the country. The various challenges surrounding the vaccination drive have been documented extensively right from the day the same was launched in January. It is obvious from the available statistics that the vaccination drive has not taken off the way it was originally envisaged. It is meandering along with stuttering and puttering aptly defines the only available means to keep the virus at a distance.
PC: Ritesh K Srivastava
- When the inoculation had to pick up pace after the Government extended the beneficiaries including 18 years and above in the first week of May, the lack of adequate supply of vaccines was acutely felt across the country failing to meet the increasing demand. Keeping this developing situation in mind, the Government in its wisdom decided to increase the gap between the first and second dose of Covishield to 12-16 weeks. However, it begs question as to whether the increase in the gap is backed by solid scientific data to justify such a move? Delving deeper into the available data on the matter would be apt to comprehend why such a move was necessitated in the first place. Two studies were cited mainly for increasing the interval.
- In a Lancet study published earlier this year, the efficacy results in the phase-3 trial of two doses of Oxford-AstraZeneca (equivalent to Covishield) was 55.1% when the second dose was given in less than six weeks. This result was from a combined analysis of the participants from the United Kingdom, Brazil, and South Africa. The results indicated that the efficacy was 81.3% when the dosing interval stretched to 12 weeks or more. Next, AstraZeneca published interim results from phase-3 clinical trials in participants from the United States in March 2021, showing vaccine efficacy of 76% against symptomatic Covid-19 when the interval between doses was four weeks. Needless to mention, the entire scenario changed when the deadly Delta or Indian variant came on to the scene.
PC: Suzi Ring
- The study conducted by Public Health England showed that two doses of Oxford-AstraZeneca administered at an eight-week interval are 92% effective against hospitalization for the Delta variant. Now, UK data which include the effects of a rapid vaccination program clearly offers evidence that the second dose should be administered quicker to get better protection against death and prevent hospitalization. Thus, there is no other way than to decrease the gap between the two doses to combat the Delta variant which is widely prevalent here. Reverting to an earlier 4-6 weeks gap would be perfect. Therefore, no sooner the Government authorities reconsider the reversal move, much better would be to ensure precious lives are protected from the virus.
