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Both Delta and Omicron variants may co-circulate: Experts



It is unlikely that anytime soon, the world will enter into pre-Covid era. Instead, it is likely that we will have to co-exist with Delta and Omicron variants of the Covid-19 in time to come as both these variants will continue to co-circulate.

This was stated by virologists and health experts at Neuberg Diagnostics’ Panel discussion on ‘VARIANTS, VACCINES and US” held in hybrid mode on Friday.

They also underscored the importance of kids’ vaccination, same shot booster doses and RT-PCR tests.

Dr.  T Jacob John, former Director, ICMR’s Centre of Advanced Research in Virology, retired professor and Head of the Department of Clinical Virology and Microbiology at CMC Vellore, emphasized on vaccinating children quickly to minimize the virus transmission and risk of emergence of new variants by mutations.

Emphasizing on vaccinating children, Dr. John said, “I am an ardent advocate of children’s vaccination with vaccines which are safe and effective, for example Covaxin. The risk of disease/death is low, but not zero even in normal children. Post-infection, they are at risk for multi-system inflammatory syndrome (MIS) and for diabetes. Children with chronic diseases are at high risk of COVID itself. But, all these can be prevented by vaccination. If children are left unvaccinated, they will act as a virus reservoir, and we know that Omicron infects children quite readily.”

“Omicron has two significant properties. One, it has extremely high transmission efficiency, far more than that of Delta; and its propensity to evade immunity induced by past infections and vaccinations. These properties are conferred by a large number of mutations on its spike protein gene,” he added.

While the Delta variant has two mutations on the receptor-binding domain of the spike protein, Omicron has 15. This has resulted in evasion from antibody binding, necessary for protection. Neutralising antibodies against the spike protein of the original virus, induced by all available vaccines (mRNA or adenovirus-vectored) are relatively ineffective against Omicron. However, recent experience shows that very high levels of antibodies that result from booster doses offer protection, especially from severe disease needing hospitalization.

Dr.  V. Ravi, former Professor of Neurovirology at NIMHANS and Nodal Officer for genomic confirmation of SARS-CoV-2 Government of Karnataka, said,“Self-test kits viz. antigen tests give reliable results in symptomatic patients; however asymptomatic patients must undertake RT-PCR tests for results especially when there is a huge surge in cases.” He remarked that current data shows that Omicron is seen more in double vaccinated people thus it is in our best interest that we don’t let our guard down.

He added, “It is wrong to expect that Covid-19 vaccine should provide us with sterilizing immunity and protection. Their primary function is to prevent severe disease and deaths. Nasal vaccines are showing tremendous amount of promise. I am sure these will provide reasonable amount of protection when availed in the market.”

On mixing of two different vaccines, he said, “There is no clear-cut data on mixing of vaccines in India. Thus, our current policy on using the same dose vaccine as a booster is in our best interest.”

Dr. V. Ramasubramanian, Consultant Infectious Diseases & Tropical Medicine, Apollo Hospitals, said, “There has been an increase in youngsters coming with high fever even in comparison to the Delta variant where the age of infection was already significantly lowered. The age limit now has been further lowered to 5 to 6 years where a temperature of 102 to 103 degrees Fahrenheit has been recorded. Interestingly, either their fever settles within 24 hours or within 4 to 5 days. These all cases are symptomatic, and they are responding to the treatment. Besides fever, they are reporting a severe throat pain. Most of them are not in condition to even swallow food. We have noticed that due to high fever and throat pain, the consumption of antibiotics has gone up in last few weeks.”

 “At our lab in Chennai, we have noticed an increase in test positivity rate (TPR) since December 28, 2021. Between December 25 and January10, out of 19,558 Covid-19 tests, TPR was 27.2%. Out of these positives, 11% were in the under 18 age group. Infections are now being recorded in the 1 to 10 years age group too. In infants under one year, two tested positive,” informed Dr. Saranya Narayan, Technical Director and Chief Microbiologists, Neuberg Diagnostics.

“Weekly TPR in our lab in Bengaluru has gone up from 5.3 to 20.6%. In our Chennai lab, from December 28, 2021 until 11 January, weekly TPR has increased from 11.1 to 34.7%. Similarly, in our Kerala lab, weekly TPR hovers around 8.41 with an increase in the last couple of days in the daily TPR.In Hyderabad, the daily TPR is around 45 % while in Mumbai (Maharashtra) it is around 40%,” added Dr. Narayan.

Regarding Omicron positivity, she saidd, “Karnataka has 50% positivity ratio, Mumbai has 40%, Hyderabad has 45% and Tamil Nadu has 80-85%.”

Experts echoed that everyone must strictly adopt personal prevention measures, use double masks, folllow hand hygiene, keep good ventilation indoors and avoid crowds and non-essential travel.

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