Will 3rd wave of Covid-19 hit India: Top expert answers
The chairman of the National Technical Advisory Group on Immunisation (NTAGI) Dr NK Arora on Thursday elaborated on a range of issues concerning the coronavirus disease (Covid-19) pandemic in India.
The chief of the Covid-19 working group said that the country is witnessing around 30,000-45000 cases of coronavirus infection every day for the past several weeks, especially from Kerala and some northeastern states and a few districts of Maharashtra.
“If we follow the genomic analysis of SARS-COV-2 viruses circulating during June, July and August, no new variants have emerged and on the basis of sero-survey conducted during July, the ongoing Covid-19 cases represent the susceptible individuals who are not yet immunised. They are affected as part of the last phase of second wave,” Dr Arora said.
In the last serosurvey conducted in July, between 66% and 70% of the people were found to be infected with the Covid-19 virus, signalling that around 30% of the people are still prone to infection. The health expert said these set of people can get infected at any time, if they are unvaccinated.
“Hence any complacency on the part of any of us throughout the country will cost hugely since the 30% people can be infected and many of them can develop severe diseases, like we witnessed during April and May this year,” Dr Arora said.
He stressed that following Covid-appropriate behaviour is both essential and critical, especially during the upcoming festive season. He cautioned that the emergence of new mutation around this time can contribute to the arrival of the third wave of Covid-19.
Efficacy of Covid-19 vaccines against Delta variant
The effectiveness values we see in media mostly refer to the effectiveness against symptomatic disease, Dr Arora said, highlighting that it is “generally 60-90% for different vaccines.”
“Most of the vaccines are not adequately effective in preventing Covid-19 infection and, therefore, it is repeatedly emphasised that even after vaccination, the person can spread the infection,” the expert said.
He stressed the need for maintaining Covid-appropriate behaviour.
The most important value of the Covid-19 vaccines is their effectiveness to prevent severe disease, need for hospitalisation and death. All the vaccines currently available in India and elsewhere are over 90-95% effective for protecting the beneficiary from severe disease and death.
Can an affected person donate plasma?
Dr Aroraa said research by ICMR revealed that plasma therapy was not useful for most patients with severe Covid-19 infection requiring hospitalisation.
Similar studies from other parts of the world have failed to prevent death or reduction in hospital stay. It for these reasons, the ICMR has removed plasma therapy as part of the treatment guidelines for severe Covid-19 infection, Dr Arora said.
“Having said that, if someone is infected, there will be generation of antibodies in their body along with cell-based immunity. Antibodies are measurable and can also be called as visible immunity. The cell-based immunity can also be termed as invisible immunity and as important as antibodies. These immunity components prevent disease and severity when such person gets re-infection with Covid-19,” Dr Arora said.
Recently an antibody mixture was introduced in the market by a company, but that did not show much benefit, he said. This antibody mixture also was based on the principle of plasma therapy. It was observed that if plasma or antibody is given to the patient in first week or early part of infection, then there can be some benefit.
A paper published recently mentions that if someone has got natural COVID infection and has recovered, then the immunity of that person will protect him for long duration and in case if such person also takes vaccine, then the individual has a double barrelled protection against infection and the disease.
What about booster dose?
The requirement of booster dose in our country cannot be decided on the basis of the situation and decisions taken in western countries, the NTAGI chief said.
“Local evidence based on the studies done in different parts of the country will guide the need for our people. This will be considered in the context when 70% to 80% of the population in our country is already infected. Overall a considerate decision will be taken based on the best available scientific evidence with the overall objective to provide optimal protection to our people,” Dr Arora said.