Manas Dasgupta
NEW DELHI, Jan 4: Even as India is witnessing a new surge forcing the authorities to impose fresh restrictions including night curfew and weekend curfew, many scientists believe that the Coronavirus pandemic is in its fag end and the newer variants of viruses will cause far less severe disease than the earlier versions.
A string of new studies has confirmed the silver lining of the omicron variant: Even as case numbers soar to records, the numbers of severe cases and hospitalizations have not. The data, some scientists say, signal a new, less worrying chapter of the pandemic.
“We’re now in a totally different phase,” said Monica Gandhi, an immunologist at the University of California, San Francisco. “The virus is always going to be with us, but my hope is this variant causes so much immunity that it will quell the pandemic.”
The omicron variant was discovered in South Africa just over a month ago, and experts caution that there is still plenty of time for the situation to change. But data from the past week suggest that a combination of widespread immunity and numerous mutations have resulted in a virus that causes far less severe disease than previous iterations.
Gandhi said while case numbers might be reaching records, omicron’s combination of high transmissibility and mild infection might signal the beginning of the end. She pointed to another study out last week from Hong Kong, which showed that vaccinated patients infected with omicron generated strong immune responses against other versions of the virus as well. This, she said, might explain why case numbers peaked quickly in South Africa. “I hope this variant creates profound immunity in the population,” she said. “It will hopefully end the pandemic.”
As the cases surged in Delhi, the authorities decided to impose weekend curfews on Saturdays and Sundays in addition to the existing night curfew even as the Delhi Disaster Management Authority (DDMA) decided to withdraw the 50 per cent curb on the buses and metro train services which had started to create chaotic conditions. The Punjab government also followed suit and decided to impose night curfew besides closing down schools and colleges while several other states closed malls, shopping arcades and cinema halls to avoid gathering of people.
India entered into newer restrictions even as a study out of South Africa found that patients admitted to the hospital there during the omicron-dominated fourth wave of the virus were 73% less likely to have severe disease than patients admitted during the delta-dominated third wave. “The data is quite solid now that hospitalizations and cases are decoupled,” said Wendy Burgers, an immunologist at the University of Cape Town.
Early on, much of the alarm over omicron was due to the variant’s large number of mutations, many of which are on the spike protein, the part of the virus responsible for helping it invade host cells. Those mutations, early data suggested, allowed the virus to easily infect not only unvaccinated people, but also to evade antibody responses from both previous infections and vaccines. But the question remained how omicron would fare once it made its way past those first lines of defense.
Several factors appear to have made the omicron variant less virulent, or severe, than previous waves of Covid-19. One factor is the virus’ ability to infect the lungs. Covid infections typically start in the nose and spread down the throat. A mild infection doesn’t make it much farther than the upper respiratory tract, but if the virus reaches the lungs, that’s usually when more severe symptoms occur.
But five separate studies in the past week suggested that the variant does not infect the lungs as easily as previous variants. In one study, released as an online pre-print by a large consortium of Japanese and American scientists, hamsters and mice infected with omicron experienced far less lung damage and were less likely to die than those infected with previous variants. Another study out of Belgium found similar outcomes in Syrian hamsters, which have been known to experience particularly severe illness with previous iterations of the virus.
In Hong Kong, scientists studied a small number lung tissue samples from patients collected during surgery and found that omicron grew more slowly in those samples than other variants did. Burgers said this change in virulence likely has to do with how the virus’s anatomy changed.
“It used to use two different pathways to get into cells, and now because of all the changes to the spike protein, it’s preferring one of those pathways,” she said. “It seems to prefer to infect the upper respiratory tract rather than the lungs.” This, Burgers said, could mean less severe infection, but also more transmissibility as the virus replicates more often in the upper respiratory tract, from which it can more easily spread.
While omicron may be good at evading the attacks of antibodies, recent studies have also shown that it has far less success avoiding the second-line defenses of vaccines and prior infections: T-cells and B-cells. T-cells are responsible for attacking a virus once it makes its way into the body’s cells if antibodies fail to prevent infection in the first place. In a recent study by Burgers and colleagues, scientists used white blood cells from Covid patients to show that about 70-80% of the T-cell response is preserved compared with previous strains of the virus. That means that for those who are either vaccinated or had a Covid infection in the past 6 months, it is likely their T-cells can recognize omicron and fight it off relatively quickly.
This latest research will need to be followed up with further study. If it holds up to additional scrutiny, it just might explain why current infections appear to be more mild than in previous waves of the virus. “When you start to see different kinds of data all pointing in the same direction, you begin to feel more confident that it’s going to hold up,” said Jessica Justman, a Columbia University Medical Center epidemiologist.
That said, as cases skyrocket, the absolute number of hospitalizations and deaths will still rise alongside them, even if those numbers tick up more slowly. “When your denominator is very large because many, many people are getting infected, you still wind up having many people going to the hospital who need care,” Justman said. Higher case numbers will also still create disruption in work, travel and schooling.
While the Delhi chief minister Arvind Kejriwal tweeted to inform that he is Covid-infected and has isolated himself at home, the BJP member of Parliament from Delhi Manoj Tiwari has also become a Covid victim. DDMA held a meeting on Tuesday to discuss the latest situation after which the deputy chief minister Manish Sisodia said most offices would have to make half their employees work from home though buses and the Delhi metro would operate at full capacity.
“DDMA has decided to impose a curfew in Delhi on Saturdays and Sundays to curb COVID surge. All government officials except for those engaged in essential services will work from home. 50% workforce of private offices will work from home,” Sisodia told reporters. “Buses and metro will function at 100 per cent but not without a mask. There is nothing to worry about. Make masks your shield.” Earlier, both services were ordered to operate at half their capacity but that led to chaotic long queues and crowds.
Delhi has reported a rising positivity rate or the number of people testing positive for every 100 tests. On Monday, 4,099 new cases and one death were reported in 24 hours. Today, cases went up to 5,481, the highest in more than seven months; three deaths were also reported. The positivity rate in Delhi has risen to 8.3 per cent from 6.46 per cent.
In the poll-bound state of Punjab, though the government has closed educational institutions and imposed night curfew amid rising Covid infections, political rallies including the one to be addressed by the Prime Minister at Ferozepur on Wednesday are expected to go ahead as per the schedule.
The state general secretary said the Wednesday’s rally, touted as “the biggest ever political rally in the state” wouldn’t be affected by Covid restrictions. The political rally of the prime minister would be preceded by an official function to be jointly hosed by the state and the central governments. “It is a joint programme of the Centre and the state government. Chief Minister Charanjit Singh Channi will also be there at the foundation laying ceremony… Hence I don’t think it will be any problem,” said Dr Subash Sharma, the BJP leader. “It will have a foundation stone-laying ceremony for a satellite centre for the Postgraduate Institute of Medical Education and Research, two medical colleges and many other projects.” The organisers said they expected about 3 lakh people would be bussed from different parts of Punjab. Another BJP leader said Congress state chief Navjot Singh Sidhu was also addressing rallies and SAD patron Parkash Singh Badal is holding village meetings in the Lambi constituency on Tuesday.