‘Booster dose won’t work, bivalent vax needed against Omicron’

Dr Santosh Bansode

The recent instance of a 29-year-old (who had returned from New York to Mumbai) testing positive for Omicron even after having taken three doses of the vaccine, has caused health care experts to raise the question on why three doses of the vaccine did not protect him.

Experts are of the view that instead of booster doses, the vaccine industry should accelerate the ‘bivalent' vaccine containing the Wuhan wild virus and Omicron virus in a single product, so that a booster with such ‘bivalent' vaccine produces the desire immunity rapidly thereby preventing the rapid spread of Omicron. Dr Wiqar Shaikh, Professor of Medicine, Grant Medical College and Sir J.J. Group of Hospitals, said that people were led to believe that the Omicron variant was mild would not need hospitalisation and would not result in deaths.

Dr Wiqar Shaikh

He recalled an article in Sunday Mid-Day on November 28, 2021, in which he had said that Omicron was more transmissible than the Delta variant and evades both antibodies as well as T-cells. He had also said that vaccines may not be effective against Omicron. Indeed, he said, Omicron is spreading rapidly around the world and has till-date resulted in seven deaths in the UK. Dr. Shaikh added that currently, there is a clamour around the world to give booster doses (3rd dose) of Covid-19 vaccine to control the spread of Omicron.

Dr Shaikh quoted a press release from the BMC which said that a 29-year-old person had returned to Mumbai from New York, on November 09, 2021, and was found at the airport to have tested positive for Covid-19. His sample was sent for genome sequencing and the results were obtained on December 17, 2021, which was positive for the Omicron variant. What is shocking Dr Shaikh said, is that this person had taken three doses of the vaccine. Dr Shaikh said that demanding a booster dose to control Omicron is without scientific evidence and that proper trials need to be conducted before demanding or approving booster doses. He said that the WHO has not yet endorsed booster doses. Dr Shaikh added that the Subject Expert Committee on Covid-19 vaccines in India had met on December 10, 2021 and concluded that booster doses are not recommended without adequate trials.

In fact, a statement from Niti Aaayog (Health) said that currently what is more important is to first vaccinate everyone in India. Dr Shaikh expressed great surprise that the CEO of Pfizer told CNBC last week that a 4th booster dose may be needed. He said that when there is no evidence as yet that a 3rd dose would work against Omicron, asking for a 4th dose is simply unscientific. The person who has tested positive for Omicron despite taking a 3rd booster is a case in point. Dr. Shaikh said that he is not surprised that all major Covid-19 manufacturers, Pfizer, Moderna, AstraZeneca and J&J are working on an Omicron specific vaccine, which should be available by March 2022.

He added that if current Covid-19 vaccines are working against Omicron, why work on a new Omicron specific vaccine; and if current vaccines are not working, then why demand a 3rd and maybe a 4th dose? Dr Shaikh pointed out that when Covid-19 vaccines were launched last year, only one dose was recommended, which after a few months was upgraded to two doses and now to a 3rd and may be a 4th dose. He suspects that Covid-19 vaccines may soon be recommended on an annual basis.

Why 3 doses of vaccine give no protection?
This question has now baffled health care experts? As we all know that most vaccines are made majorly targeting spike proteins of Covid virus and in Omicron variant there are many mutations in spike proteins, hence, I am of the view that there's a high chance that vaccines won't be able to protect us fully from this variant, opined Dr Santosh Bansode, Head of the Department, Emergency Medicine, Wockhardt hospitals, Mumbai Central. "It's expected that those vaccines will still protect us from getting severe symptoms. Some immunity is better than no immunity.

We have seen up till now that vaccines are giving us immunity against Covid which will help us get some protection so that we won't get severe symptoms and overall mortality will be less," he said. "One fear is that Omicron will infect an unvaccinated or a person with comorbidities and then might cause severe symptoms in such patients and even can cause death. Since it is spreading at a faster rate, if we don't take much precautions, the number of patients will increase and there is a chance that the vulnerable population will be at risk. We must also keep in mind that children are not yet vaccinated and, in most schools now children are attending physical classes. We should follow very strict Covid protective protocols in schools," Dr Bansode concluded.

Confusion over hypothesis

Dr Ketan Vagholkar, Professor of Surgery at DY Patil Medical College said, "Reports of Omicron positivity in fully-vaccinated travellers with booster doses entering our country are creating unnecessary confusion. Vaccines all over the world were prepared after studying the original strain of Covid-19 virus in 2020. The vaccination was then started towards the end of 2020 for healthcare workers and subsequently for the general population in 2021. The Delta variant emerged much latter and infected the majority of the population, which included both vaccinated as well as non-vaccinated individuals.

Dr Ketan Vagholkar

This proved that vaccination was not protective against the delta variant but claimed to reduce only the severity of the disease. Omicron is now the next variant which has emerged whose pathogenicity seems to be quite mild. Various hypothesis postulating a third jab to be effective against the Omicron variant have been proposed. However, there is no authentic scientific data to prove this. Hence one should not get misled by the hypothesis of multiple jabs being protective. Strict Covid appropriate behaviour with completed two-dose vaccination is the best way of prevention."

Expert view

Is there evidence that Omicron evades immunity, and will booster vaccine help?
Accelerate the ‘bivalent' vaccine
"Scientific publications and WHO review meetings across the world are taking a deep look at studies that can provide some evidence of Covid variants, including Omicron, to see if these are evading immunity in fully vaccinated individuals. Populations have received multiple vaccine products so far.

"Some 30-40 studies recently reviewed were primarily the ones that were based on immunity markers in individuals who had primarily received mRNA vaccines of Pfizer/Moderna. Most studies were of experimental design and found that of 247 neutralising antibodies that are normally produced in the body after Covid-19 infection and/or vaccines, 57 (approx. 20 per cent) of neutralising antibodies showed 7-20 fold reduction in fully vaccinated people having breakthrough infection with Omicron. Most of these declined neutralising antibodies were ones that were directed towards non-prominent parts of the virus envelope. In simpler words, these declined neutralising antibodies may not be of much protection to the individual; moreover, these are not standardised to-date. When these individuals were given booster injection, 247 neutralising antibodies increased within one month.

But reassuring findings were that cell mediated immunity, mainly comprising of CD4 and CD8 cells in human body remained intact in vaccinated individuals despite some decline in neutralising antibodies directed towards non-prominent parts of virus envelop," said Dr Subhash Hira, Professor of Global Health, University of Washington-Seattle and member of WHO-Geneva Covid review groups.

Dr Subhash Hira

Dr Hira added, "The reviewing scientists raised the following points to counter finding of neutralising antibodies as laboratory-based (in-vitro) interim findings: a) The level of neutralising antibodies occurring in humans (in-vivo) will be a more reliable parameter. b) The breakthrough infection seen with omicron among individuals who had received three injections of mRNA vaccine does suggest that a booster dose raising neutralising antibodies in one month did not help to ward off omicron infection. Interestingly, there is no data yet to show breakthrough Omicron infection among individuals who received Covid-19 inactivated Covaxin or vector-based Covishield vaccines. c) The cell mediated immunity has remained intact despite the Omicron infection, and that is very reassuring. d) The most important parameter of vaccine efficiency is the ‘clinical outcomes and death' in vaccinated individuals. No such clinical studies have appeared as yet with any vaccines. e) While the world is catching up with unvaccinated populations, the vaccine companies may wish to prepare and escalate next generation ‘bivalent' vaccines using the Omicron variant. f) Since the case-doubling time of omicron is 1.5 to 3 days and is considered too fast, any booster dose given now may not produce any neutralising antibodies for the next one month or more! In other words, a booster may not be the final solution of this pandemic of Covid-19 variants," Dr Hira said.

"The UK, most of Europe, and the USA are having large waves of Omicron as breakthrough infections despite 60-75 per cent of the population having received a full dose of two mRNA vaccines and now booster injection to >0.5m people each day. By comparison, the Indian vaccines that contain vector-based virus or the inactivated whole virus seem to have produced a wider base of immunity protection, even against the variants, including Omicron. It will remain to be seen if India escapes high deaths being feared due to Omicron, while the northern countries are anticipating the winter double-whammy caused by omicron," he concluded.

Also Read: Maharashtra reports six more Omicron cases; state tally now 54