A pilot study, done on 20 such individuals, who never contracted Covid-19, shows that first shot of both the vaccines - Covaxin and Covishield - help develop antibody from the second week onwards.
In his study, Professor Choubey recruited 20 volunteers and divided them into two groups of 10 each – One group received Covaxin, the other was administered Covishield.
A pilot study, done on 20 such individuals, who never contracted Covid-19, shows that first shot of both the vaccines - Covaxin and Covishield - help develop antibody from the second week onwards.
A group of researchers led by Professor Gyaneshwar Chaubey from the genetics department at the Banaras Hindu University had previously conducted a pilot study on Covid-19 recovered persons and concluded that such individuals develop anti-body faster than those who never contracted the virus. Outlook had reported the study on May 5.
Professor Choubey tells Outlook that he has been conducting studies to see the effectiveness of one shot on various individuals.
“These are indicative studies. The government can enlarge its scope for taking policy decisions,” Choubey and his team said.
They added, “We have to stop the third wave and vaccination is going to be crucial for that. If one shot can protect some individuals, why waste a second shot on them. The second one can be used on someone else to protect his or her life.”
The study is in line with the government’s decision to increase the gap between the first and second doses of the Covishield vaccine. However, it also suggests that the government can increase the similar gap between the two doses of Covaxin as well.
In his study, Professor Choubey recruited 20 volunteers and divided them into two groups of 10 each.
While one group received Covaxin, the other one was administered Covishield. He monitored their titer antibody every week for four weeks and observed that 8 volunteers out of 10, who were administered Covaxin, developed antibodies within the second week of inoculation.
While one volunteer showed antibodies in the third week, the remaining one didn’t develop any immunity in four weeks of the observation period.
On the other hand, those who got Covishiled developed anti-body in the third and fourth week.
While five volunteers developed immunity in the third week, four did it in the fourth week. One didn’t develop any immunity.
Professor Chaubey admits that his study is very small, however, he feels that this can lay a foundation for bigger research which might prove beneficial in the long run.
“The bottom line is that both vaccines can develop antibodies after the first shot,” He said.
For the first time, any such study to see the speed of antibody production has happened in India. So far, there is no government research body working on similar lines.
Dr NK Arora, Chairman of India's Technical Advisory Group on Covid-19 vaccination, confirms that there is no plan to carry out any such study on single-dose effectiveness, however, he says that the vaccine tracking platform will monitor those people who have not taken a second dose on schedule for various reasons.
“We will closely monitor such people and we will be looking at various kinds of outcome particularly breakthrough infection or any hospitalization and death in these individuals which will give us a measure of vaccine effectiveness in the real world,” Dr Arora told Outlook.
Internationally attempts are being made to assess the benefits of one shot on individuals.
On April 23, 2020, the peer-reviewed British Medical Journal (BMJ) published a preliminary result from a large UK surveillance study which indicates that “Infections of SARS-CoV-2 fell by 65% after a first dose of the Oxford-AstraZeneca or Pfizer-BioNTech vaccines.”
“The protection from new infections gained from a single dose supports the decision to extend the time between first and second doses to 12 weeks to maximize initial vaccination coverage and reduce hospitalizations and deaths,” Koen Pouwels, senior researcher in Oxford University’s Nuffield Department of Population Health and co-lead author of the study was quoted as saying in the study.
Health experts suggest that the government should identify two or three districts where the maximum population has been vaccinated and carry out such a study.
Dr. Syamal Roy, a noted immunologist, who retired as Head of the Department of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, Kolkata is the view that it is important to see if the antibody that forms is enough to fight against the virus.
“I think we need to see the ability of the antibody to neutralize the antigen in the experimental system on a large sample size,” Dr Roy suggested.
One of the principal investigators of the clinical trial of the Covishield vaccine, Dr Sanjay Lalwani from Bharati Vidyapeeth (Deemed to be University) Medical College and Hospital, in Pune seconds with Dr Roy.
Dr Lalwani said, “The government has already increased the gap from 6 to 8 weeks to 12 to 16 weeks between the two doses of Covishield. They can identify maximum vaccinated areas like Pune and check the antibody of the individuals on monthly basis.”
Dr Manish Kumar Jain, who was one of the principal investigators of the clinical trial of Covaxin says that a similar study is required for Covaxin as well.
Dr Jain, who is head of the Department of Pulmonology, Maharaja Agrasen Superspecilaity Hospital, admits that this aspect was not analyzed during the clinical trial at his Centre.
Renowned virologist Dr. Jacob T. John said, “If the purpose of the study is to find out protection after one dose and if the vaccine manufacturing companies haven’t looked at this aspect, then the study has some curiosity value.”
Dr John said that he hasn’t seen anybody doing such a study to look at the speed of antibody protection.