Fourth wave in India seems unlikely due to high exposure and vaccination coverage, experts say

Several parts of the world have reported an increase in new Covid-19 cases, but in India experts believe that unless a deadlier variant of the virus emerges, the country is unlikely to see another. wave of infections.

The widespread exposure of the Indian population to the virus, especially during the deadly second wave in the summer of 2021, followed by widespread vaccination coverage, may have given them a higher degree of immunity compared to d other countries with high vaccination but low past exposure. , say epidemiologists.

On March 18, India reported 2,528 new cases of Covid-19, a marked decrease from the nearly 27,000 new infections recorded through mid-February as the third wave fueled by the infectious variant of Omicron waned. More than 80% of the adult population has received both doses of Covid-19 vaccines.

While the number of daily cases in India is steadily decreasing, several other countries are reporting an increase in the number of cases. China is seeing a record rise in infections, the highest since the pandemic first broke out in the city of Wuhan in December 2019.

Cases on the mainland peaked at 5,280 on Tuesday, according to AFP. Such figures were noted at the start of 2020 when the country recorded 3,000 to 5,000 cases per day.

China, which follows a zero-Covid policy, has imposed strict restrictions in several parts of the country. China’s rise is driven both by Delta and Omicron variants. A subline of Omicron, BA.2, also called Stealth Omicron, is spreading rapidly among the Chinese population.

The Robert Koch Institute, which monitors the pandemic situation in Germany, said the country had reported 2 94,931 new cases the 17th of March.

Other European countries, such as Finland, Switzerland, the Netherlands, Italy and the UK, have also reported high numbers where the Omicron BA.2 subline is spreading. Almost 65% of the European population has been fully vaccinatedaccording to Our World in Data.

South Korea, which has won praise for keeping infection numbers low, has recorded more than six lakh cases on March 17, the highest since January 2020. At least 87% of the South Korean population has been fully vaccinated, with boosters also rolled out for vulnerable people.

On March 17, Tedros Adhanom Ghebreyesus, the director general of the World Health Organization, said cases had started increasing globally after several weeks of decline.

Rising cases in countries with high vaccination and booster rates have raised concerns. In India too, the forecast of a fourth four-month wave starting at the end of June has raised alarm.

The study, carried out by the Department of Mathematics and Statistics at the Indian Institute of Technology, Kanpur, was published MedRxiv. It has not yet been peer reviewed.

The results, which are based on mathematical modeling called Sutra, do not predict pressure on health infrastructure in the event of a fourth wave. Epidemiologists believe, however, that the downward trend in Covid-19 cases will continue in India.

High immunity in Indian population

Virologist Dr T Jacob John said the current outbreak in several other countries is due to the highly infectious Omicron variant.

India witnessed the third wave of the pandemic, fueled by the Omicron variant, between January and February due to Omicron, when new daily cases peaked at 3.47 lakh on January 21.

According to data shared by the Union Ministry of Health and Family Welfare on Thursday, India recorded 77.42 lakh cases of Covid-19 during the third wave which spanned 42 days. The third wave ended on February 14, according to the ministry.

“It’s like swimming in a river,” John said. “We in India have crossed this river, other countries are still swimming there.” According to the virologist, the spread of Omicron has been delayed in Europe, China and Korea. “The uptick we’re seeing now in these countries is because of that,” John said. He also said high vaccination rates helped keep the Omicron wave relatively mild in India.

At the start of the third wave, India had covered almost 90.8% of its adult population with a single dose of the vaccine while 65.4% had received both doses. During the third wave, 27,118 deaths were recorded compared to 2.52 lakh deaths during the second wave in April and May last year. Single-dose vaccination coverage in the adult population at the start of the second wave was 10%.

Public health expert Dr Chandrakant Lahariya said countries that first vaccinated a large portion of the population, which was then exposed to the virus, see more infections with severe symptoms than countries where the population was first naturally exposed to the infection and then vaccinated.

“The combination of immunity developed due to natural exposure and immunity generated by vaccination works strongly against the virus,” Lahariya said.

He said India had also experienced a surge carried by the Delta variant over the past summer, which had also immunized the population against serious infections. “The Covid-19 pandemic is over for India,” he said.

Lahariya said that in the case of China, the country has never recorded a natural infection like India has. “The majority of its population is still susceptible,” he said. Both China-made vaccinesCoronaVac and Sinopharm, have the lowest efficacy compared to all other vaccines, according to Lahariya.

He said South Korea also had an early surge, which was followed by a long period without a significant rise in cases, making its population more susceptible.

Seniors at risk

A country’s demographics also play a role in infection susceptibility. Dr Gagandeep Kang, a microbiologist at Christian Medical College, Vellore, said European countries had a higher share of elderly citizens and therefore continued to witness more infections and hospitalizations than India.

According to Kang, a person who receives both shots of the Covid-19 vaccine after recovering from an infection has stronger protection compared to someone who receives two doses and a booster.

“Since a large part of the population has been exposed to the virus and has been vaccinated, it is safe to assume that people have better protection,” she said.

Kang said that unless a new variant emerges, more severe than Delta and more transmissible than Omicron, there should be no concern about another wave in the country.