RESEARCH ON THE BF.7 VARIANT IS STILL IN THE WORKS. BASED ON PREVIOUS DATA, IT CAN BE ESTIMATED THAT THE EFFICACY OF CURRENT VACCINES AGAINST THE NEW VARIANTS HAS DECLINED IN VARYING DEGREES, SAYS DR RAJESH PAREKH, HON. DIRECTOR, MEDICAL RESEARCH, JASLOK HOSPITAL AND RESEARCH CENTRE, AND AUTHOR OF TWO NATIONAL BESTSELLERS ON COVID-19 AND VACCINATION
India officially recorded 188 new coronavirus cases on Wednesday, December 28, compared to 65 exactly a week ago.
Should we worry about the new surge of Omicron in China and far-eastern and Southeast Asian nations given our geographical proximity? But given that the BF.7 variant has a greater immune escape potential and a shorter incubation period, the Government is in alert mode, preparing healthcare infrastructure and making testing mandatory for all travellers coming from five countries to begin with. Prevention is the best strategy against a rapidly evolving and adaptive virus, says Dr Rajesh Parekh, Hon. Director, Medical Research, Jaslok Hospital and Research Centre, and author of two national bestsellers on COVID-19 and Vaccination. He even recommends a fourth vaccine shot for frontline healthcare workers.
The BF.7 variant has previously been detected in India but did not spread as much. Is it likely to cause a surge?
Indeed. Not a
worrisome one, though. India officially recorded 188 new coronavirus cases on
Wednesday, December 28, compared to 65 exactly a week ago. A surge is expected
in January 2023. The BF.7 variant has the strongest infection ability of all
Omicron sub-variants like BA.1 and BA.2.
Its R0 (the rate of
infectivity) is estimated to be higher than 10, possibly even R18.6. This, on
the lower side of the estimate, translates into one case becoming a billion
cases in nine steps. Besides, BF.7 has a higher immune escape capability and a
shorter incubation period than all previous variants. Unfortunately, the virus,
like many others, has so far always been a step ahead of us. So, we cannot be
certain of what it will do next and when. We should always be prepared for a
worst case scenario while hoping for the best.
With Omicron variants mostly leading to upper respiratory tract infection, what is the most effective way of maintaining surveillance, given that most people are unlikely to get tested or test using a home kit?
The WHO has provided
periodically revised guidelines on ideal surveillance of COVID-19. The purpose
of surveillance is to identify changes in epidemiological patterns, trends and
to accordingly prepare the healthcare capacity. In their new revision, they
have added the importance of genomic surveillance to identify the
sub-variants that are in circulation. While it is indeed a challenging
task, continuing testing and serosurveys in priority groups are the most
effective methods for planning policy. The Tata Institute for Genetics and
Society (TIGS), Bengaluru, has been conducting environmental surveillance of
COVID-19. It has been collecting wastewater samples from 28 Sewage Treatment
Plants (STPs) in Bengaluru since August last year to monitor real-time spread
of Covid. Similar testing can be conducted in other areas of India as well.
Is there a need to revert to work-from-home routines and mask mandates to prevent a surge?
Prevention is always
a good strategy. Even though India is not seeing a substantial surge at the
moment, maintaining social distancing, wearing masks as well as respiratory and
hand hygiene measures can go a long way to curtail surges. The Institute for
Health Metrics and Evaluation (IHME) estimated that cases are 133 per 100,000
people while the reported cases are 0.74 per 100,000 people. So, there is a
substantial gap between reported and estimated cases. Cases can be reduced by
half if 80 per cent of the population reverts to wearing masks.
Are the current vaccines effective against BF.7?
Global vaccination
campaigns have resulted in considerably improved control of SARS-CoV-2.
However, a study in the New England Journal of Medicine on vaccine efficacy
against the Omicron B.1.1.529 variant reported ChAdOx1 nCoV-19 (Covishield) did
not provide protection after 25 weeks of two doses; the efficacy, however,
increased with booster shots. A meta-analysis in the Lancet reported that one
month after the primary vaccination (two doses), vaccine effectiveness against
severe COVID-19 disease was lower for Omicron compared to other variants.
Vaccine effectiveness against Omicron decreased rapidly from one to six months
after the primary vaccine series. Research on the BF.7 variant is still in the
works. However, based on previous data, it can be estimated that the efficacy
of current vaccines against the new variants has declined in varying degrees.
Is there a need for a fourth dose, especially among healthcare workers who are at the frontline?
Yes. A meta-analysis
in the Lancet suggested that booster vaccination increased vaccine
effectiveness against Omicron-induced severe disease. The immunity built by
boosters remained high four months after vaccination.
Does India also need a bivalent vaccine like those that have already been approved outside India?
The new booster is a
bivalent vaccine, which means it contains two messenger RNA (mRNA) components
of the coronavirus. One half of the vaccine targets the original strain, and
the other half targets the BA.4 and BA.5 Omicron sub-variant lineages, which
are predicted to continue circulating this fall and winter.
In a preprint
published in December 2022 on medRxiv, researchers evaluated the bivalent [encoding
spike (S) proteins of severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2) D614 strain and the Beta variant of concern (VOC)] vaccine
efficacy (VE) against the Omicron VOC. India was among the countries the second
stage of the study was conducted in. The study found that the bivalent COVID-19
vaccine conferred heterologous immune protection against symptomatic Omicron
BA.1 sub-VOC and Omicron BA.2 sub-VOC infections among adult individuals with
prior SARS-CoV-2 exposure.
With lakhs of people continuing to get the infection, could a more transmissible or a more virulent variant arise?
It is possible though
not probable. There have been four major variants of SARS- CoV -2 and over 50
mutations that have been identified. The virus is rapidly changing and adapting
to us. We cannot predict how many variants may emerge and how they may change.
The trend so far suggests the virus is getting faster and stronger in its
ability to infect. However, it is less severe in its lethality. Vaccination and
infection-induced immunity have a major role to play in this as well. We must
always keep in mind that the COVID-19 pandemic is NOT over. We need to continue
working at the individual and collective levels to emerge triumphant from this
monumental disaster.
Why Dr Parekh?
Dr Parekh trained at
the K.E.M. Hospital, Mumbai and the Johns Hopkins University School of
Medicine, Baltimore. He has over 150 publications in journals such as Lancet,
American
Journal of Psychiatry, British Journal of Psychiatry, Archives of General Psychiatry, Archives of Neurology and Stroke and has written 20 book chapters. He has extensive research experience across the world in basic and clinical research, having participated in over 75 research projects. He has been invited to lecture at the Harvard Medical School, the Johns Hopkins University School of Medicine, and the Institute for Research in Neuroscience and Neuropsychiatry in France.
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