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Senior citizens wait in line at a COVID-19 vaccination center in Mumbai. This week, the Indian government announced that everyone over 45 can get a shot starting on 1 April.

Pratik Chorge/Hindustan Times via Getty Images

COVID-19 is soaring again in India. Can vaccines stop it?

Science’s COVID-19 reporting is supported by the Heising-Simons Foundation.

Mumbai—Just over 1 month ago, many Indians believed the pandemic was winding down. Cases of COVID-19 had declined continuously and dramatically for 5  straight months, travel restrictions had been lifted, and wedding season was in full swing. In Mumbai, the local commuter trains were fully back in service on 1 February.

But now a second wave is hitting. Nationwide, cases have soared from just over 11,000 daily in mid-February to more than 50,000 per day this week, more than half of them in Maharashtra state, of which Mumbai is the capital. The remainder are concentrated in five other states, but scientists worry the disease may soon surge across the country again. India is fighting the rise with new restrictions and efforts to step up vaccination. But although the country produces two authorized COVID-19 vaccines, its immunization campaign has yet to gather steam.

Coming after India’s first giant wave of cases, which peaked in September 2020, the spectacular decline defied dire predictions. Antibody surveys, which suggested that densely populated areas in cities such as Delhi and Mumbai were near herd immunity, raised hopes that transmission was burning out. (Other Asian countries also did relatively well, leading some to speculate that their populations were somehow less vulnerable to COVID-19.)

But the optimism may have been unfounded; a more recent survey across 700 districts found only about 22% of Indians had been exposed overall. Meanwhile, control measures such as masking were loosened, travel and social gatherings increased, and testing and contact tracing stumbled. “We let our guard down too quickly,” says virologist Shahid Jameel, director of the Trivedi School of Biosciences at Ashoka University.

Mutations may also be reigniting the pandemic. About 736 of more than 10,000 samples sent for genomic sequencing in recent months tested positive for B.1.1.7, a variant first discovered in the United Kingdom that is known to be more infectious. In Punjab, it was detected in 81% of 400 sequenced samples. Scientists are also investigating a variant with two mutations, E484Q and L452R, found in certain districts that are seeing an exceptional surge in cases. The two mutations are associated with “immune escape,” or an ability to elude antibodies, and increased infectivity, health ministry officials said this week, although there is no evidence yet that this variant is causing the surge.

Climate could play a role as well. Some scientists say India's epidemic may have a seasonal pattern opposite to that seen in Europe and the United States, where winter drives people indoors, where the virus spreads easily. In India, the summer heat may lead people to retreat to the fans and air-conditioners of their homes, says Prabhat Jha, an epidemiologist and director of the Centre for Global Health Research, co-sponsored by St. Michael's Hospital and the University of Toronto.

Meanwhile, less than 5% of India’s 1.3 billion people have received at least one dose of vaccine. The AstraZeneca vaccine, manufactured by the Serum Institute of India, accounts for most of the 55 million shots delivered so far. The other locally produced vaccine, Covaxin, was developed by Bharat Biotech in collaboration with the Indian Council of Medical Research. Both vaccines require two doses.

We were lucky compared to what might have been. But the story is not over. The virus keeps surprising us.

Giridhar Babu, Public Health Foundation of India

The government is striving to accelerate the pace, currently about 2 million to 3 million shots per day. “My magic number is 10 million doses a day, to cover 300 million in as short a time as possible,” says epidemiologist Giridhar Babu of the Public Health Foundation of India. This week, the government announced that everyone over age 45 can get a shot starting 1 April.

Officials have said vaccine supply would not be an issue, but Reuters reported on Wednesday that India has put on hold exports of the AstraZeneca vaccine to help meet domestic demand. India has exported 60 million doses to some 80 countries since January, through bilateral aid—called “vaccine diplomacy” in the national media—commercial contracts, and the COVID-19 Vaccines Global Access Facility, a global scheme to increase access to the vaccine. Earlier this month the Serum Institute of India, one of the world's largest vaccinemakers, had warned that shortages of raw materials, due in part to temporary U.S. curbs on exports, could hit its vaccine supply.

Whereas the middle and upper classes have been flocking to get their shots, fewer poor people have turned up. Social workers attribute this to a combination of low awareness and day workers’ inability to take time off. In Mumbai, authorities have begun to set up vaccination camps in slums. Also needed, says Arun Kumar, head of Apnalaya, a nonprofit that works in the city’s slums, are “massive community-based programs to clear vaccine fears.”

Exponential growth returns

After a sharp 5-month decline, COVID-19 cases are rising rapidly in India. Most new cases are in eight states, but scientists worry about a nationwide surge. 

Daily cases in thousands (7-day average) 0 25 50 75 100 Mar. 2020 Jun. 2020 Sep. 2020 Dec. 2020 Mar. 2021 28 March

Some of the fears stem from Covaxin's hasty approval in early January, before data from phase 3 trials were available. “It created a doubt,” says former federal health secretary K Sujatha Rao. “Once trust is broken, it’s not easily regained.” On 3 March, Bharat Biotech announced the vaccine had 81% efficacy, based on an as-yet-unpublished initial analysis of 43 cases. The company plans to do another interim analysis after 87 cases, and a final one after 130 cases.

Reports of violations of informed consent in trials and inadequate transparency around adverse events may have also shaken confidence. On 16 March, a group of 29 doctors and researchers wrote a letter about reported deaths of vaccinees—80 so far since the immunization drive started in January. Although the vaccines may not have caused the deaths, the petitioners say, the government should investigate them and disclose the findings. Unlike at least 20 European countries, India has not paused use of the AstraZeneca vaccine after reports of serious clotting disorders, but officials have said they are reviewing the data. 

In an attempt to slow the second wave, several states and cities have reintroduced curbs on social gatherings, imposed temporary lockdowns, and stepped up testing and tracing. In Mumbai, once again a hotspot of the pandemic, the city banned public celebrations of the spring festival of Holi this coming weekend. The state of Uttarakhand, however, removed restrictions on the Mahakumbh, a religious congregation held every 12 years, allowing some 3 million people to gather on the first day of the festival, 11 March. Some of those restrictions were reinstated this week. 

“We were lucky compared to what might have been,” Babu says. “But the story is not over. The virus keeps surprising us.”