2022 was expected to be a year of hope. A year when the COVID pandemic that had killed millions and wrecked economies around the world, would come to an end. But then arrived Omicron, a heavily mutated new variant. First detected in South Africa in November, it triggered a new wave of COVID-19 in Africa, Europe, and America.
And in India, as the new year dawned, cities like Mumbai, Chennai, Calcutta, Bengaluru, and Delhi started seeing ever-increasing single-day spikes in COVID cases in nearly seven months. There were also wide variations in Test Positivity Rates (TPR) across the country likely caused by variations in testing strategy.
In absolute number terms (figures as of January 3rd), Mumbai was the highest with 8082 new cases and Hyderabad the lowest with 294. No figures were however available for the TPR in these two cities. Calcutta was the outlier, with 2801 cases but a TPR of 33%.
It is not clear how and why the TPR was so high in Calcutta while Bengaluru (1049 new cases, TPR 2.36%, a 1.3% increase over the previous day), Delhi (4099 cases, TPR 6.46%, a 2% increase in a single day) and Chennai (876 new cases, TPR 3.6%, no significant increase over previous days as yet) seemed more manageable.
The number of Omicron infections in the new cases is a moving figure, given the time gap in sequencing the samples and the lack of a uniform updated database of cases state-wise and city-wise. As of Jan 3rd, Chennai had reported 92 Omicron cases, Mumbai 368, Telangana 181, and Karnataka 87 cases.
WHO and Indian health authorities emphasise that though highly infectious, Omicron causes only mild symptoms as compared to the more severe symptoms caused by previous variants like Delta. In fact, Delhi’s health minister has said that despite the increase in TPR, there has been no significant increase in patients requiring hospitalisation.
Experts say that while an Omicron wave is highly likely in India in the coming months, it is likely to be less severe than the Delta wave of 2021, due to higher population immunity against COVID-19. According to the findings of a national serosurvey last July, nearly 70% population of the country was found to have antibodies against the virus.
Besides, vaccine penetration in India increased post-second wave, with over 90% of adults having received at least one dose and 61% fully vaccinated. “With only 5% of them having received their first dose before the second wave, vaccination in India is mostly post-infection and is expected to lead to more effective ‘hybrid immunity’,” says Dr Anurag Agrawal, Director, Institute for Genomic and Integrative Biology, New Delhi.
“After infection and recovery, even one dose of vaccine induces a fast, diverse, and powerful immune response. Our study shows such immunity was significantly more effective against the Delta variant than that from the vaccine alone. Whether this will also be true against Omicron is not known.”
Unvaccinated most vulnerable
Dr Agrawal feels that immunity through natural infection was why the Omicron outbreak in South Africa was milder. South Africa had recently reported 70% seropositivity rate following a large Delta wave. However, he warns that the high potential of Omicron to cause reinfections and vaccination breakthroughs mean that there is no herd immunity protection whatsoever for those without prior immunity. While the vaccinated or recovered groups may have a very low incidence of severe disease, the same may not be true for the many vulnerable unvaccinated.
Dr Padmanabha Shenoy, Consultant Rheumatologist and Medical Director, CARE (Centre for Arthritis and Rheumatism Excellence), Kochi, and his team conducted a study on 1500 people to look at the immunity levels of people who got both natural infection and vaccine. He found that though a fully vaccinated individual on average has antibody titres of 322, those who developed immunity after infection and vaccination, have antibody titres exceeding 11,100. This dramatic increase in the antibody titres provides robust protection against severe disease.
The study recently published in The Lancet shows that the infection plus vaccinated group also had a higher neutralisation capacity, the ability of antibodies to block virus infection (87% of individuals with at least 30% neutralisation). “These findings suggest that countries like India which were severely affected by the Delta variant and are widely vaccinated after the second wave are in a much safer position this time,” says Shenoy.
No room for complacency with Omicron
But experts emphasise that people cannot afford to be complacent. The virus, says Dr N K Arora, a member of the National Covid-19 Task Force, is still amidst us and even if a small part of the population in India gets infected, it will translate into a huge number of cases.
“We don’t know much about the new mutant and its immune escape capability, but masks work against all mutants, so wear them,” advises Dr Arora. “Our new year resolution should be to follow COVID-appropriate behaviour”.
The lessons learnt in 2021 should help people and policymakers tackle the pandemic better in the coming year. The government has already deployed multidisciplinary central teams in 10 states which are either reporting an increasing number of Omicron cases, or have a slow vaccination pace, to help the state and district administration with COVID management. The states include Kerala, Maharashtra, Tamil Nadu, West Bengal, Mizoram, Karnataka, Bihar, Uttar Pradesh, Jharkhand, and Punjab.
These teams will send samples from clusters to the government’s INSACOG lab network for genome sequencing; help enforce COVID-appropriate behaviour, and make sure that there are sufficient hospital beds, logistics including ambulances, ventilators, medical oxygen, etc. to tackle any surge in hospitalisation. They will also push vaccination numbers in these states.
Experts say that a case positivity rate of below 5% for two weeks is necessary to contain any outbreak. “There are regional variations, as some states are still reporting a very high number of cases,” said Rajesh Bhushan, health secretary, at a recent pandemic briefing. “What is cause for concern for us is that the case positivity rate in Kerala, which is 6.1%, and Mizoram, where it is 8.2%. Compared to the national case positivity rate, both the states are showing very high case positivity.”
On vaccination, at least 11 states have vaccinated a lesser number of people than the national average, for both the first and second doses, according to the health ministry.
New COVID vaccines
In the last week of 2021, Central Drugs Standard Control Organisation (CDSCO) added two more vaccines to the basket by giving emergency use authorisation to Biological-E’s CORBEVAX vaccine and Serum Institute of India’s (SII) COVOVAX. Besides, it also approved the drug pill Molnupiravir for emergency use. The drug is said to help those with mild to moderate symptoms.
Booster dose for select groups
On December 25, Prime Minister Narendra Modi announced that from January 3rd, children between the ages of 15 to 18 will get the vaccine. Plus people aged 60 and above with comorbidities, at high risk of developing severe disease, will be eligible for booster doses and healthcare workers, who are at high risk of catching the infection, will be getting ‘precaution’ doses.
While two vaccines have received Emergency Use Authorisation for use in children in India—Zydus Cadilla’s ZyCovD vaccine, the world’s first plasmid DNA vaccine, and Bharat Biotech’s Covaxin—the government will inoculate children with Covaxin for now.
Countries like the US, Egypt, Vietnam, and Mexico have already begun vaccinating children of various age groups. In fact, several countries, Canada, Italy, France, and Spain for instance, are vaccinating children as young as five.
In fact, the US Food and Drug Administration has expanded emergency-use authorization for a booster dose — a third shot at least six months after their second vaccine dose of the Pfizer-BioNTech COVID-19 vaccine — for those in 16-17 age group
Booster doses, experts feel, may help bring down the severity of disease in the most vulnerable population. Some studies show that mortality due to COVID-19 in susceptible populations is around 1.5 percent, which means about 15,000 deaths, per million cases. Vaccination, opine experts, can prevent 80-90% of these deaths.