A tweet posted by Haryana’s Health Minister Anil Vij sparked a social media frenzy on Saturday afternoon. The seemingly simple tweet announced that Vij had tested positive for COVID-19
. “I was tested positive for Corona. I am admitted to Ambala Cantt Civil Hospital. Everyone who has been in close contact with me is recommended to have a corona test (sic),” he said.
Netizens were quick to point out that he had participated in Bharat Biotech’s phase III trials coronavirus Covaxin vaccine just two weeks ago. Experts, however, say that the fear and anxiety that followed are unfounded.
Speaking to News18, Dr Rajeev Jayadevan, former president of the Indian Medical Association, Cochin explained that the minister’s positive result could be misinterpreted as a vaccine failure. Bharat Biotech also said that Covaxin clinical trials are based on a two-dose schedule, administered 28 days apart. The efficacy of the vaccine will be determined 14 days after the second dose.
Efficacy data should generally be reviewed after 15 days of the full dose. In this case, Anil Vij is presumed to have received the first dose. This is also unclear, as Bharat Biotech’s Phase III trials are double-blind and randomized, where 50% of the subjects will receive the vaccine and the rest will receive the placebo. The Ministry of Health in a statement suggested that the minister received an injection and not a placebo. Bharat Biotech in its statement did not say anything about it.
Jayadevan said that this point is only of academic interest. “Academically, it will be interesting to see if he got the actual dose of the vaccine or the placebo, and if he developed neutralizing antibodies after the first dose.”
“This is because the body’s adaptive immune response takes time. Neutralizing (protective) antibodies peak in the month after the second dose of the vaccine,” he added.
In other words, experts say, any event that occurs earlier is not counted as a result.
JUDGMENTS EXPLAINED
So what exactly are double-blind, randomized clinical trials? In placebo trials, the volunteer receives a dummy injection or a vaccine that is a meningococcal vaccine, so the placebo group will also benefit from it.
A double-blind trial is when half of the participants or a fixed proportion of participants receive a test drug and others receive a placebo. That is the concept of randomization.
Double blind means that neither the participant nor the person administering the vaccine know what the volunteer has received. “This means there is no bias. The concept of linkage is to eliminate bias,” says Dr. Jayadevan. “In research, one of the biggest enemies is bias.”
If the caregiver knows whether the patient received the drug or the placebo, their assessment will be biased.
Blinding can be single or double. In a single-blind study, the clinical trial participants do not know whether they are receiving the placebo or the actual treatment. In a double-blind study, both participants and experimenters do not know which group received the placebo and which group received the experimental treatment. The method, experts say, superior, the objective, to eliminate bias.
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