How is India’s second wave of Covid-19 different from the first?

With a massive second wave of Covid-19 sweeping through India, one in five infections in the world is currently being reported from the country.

How is India’s second wave different from the first?

To start with, the second wave is spreading much, much faster than the first, as visible in this graphic.

Many experts believe the surge is partly fuelled by new strains of the coronavirus, including a more infectious homegrown variant found in 61% of samples genome sequenced in Maharashtra, the worst hit state. The laxity in preventive measures, coupled with the presence of new variants, has resulted in a nationwide crisis. Many states are reporting shortages of hospital beds, oxygen supply, medicines, even space in morgues and crematoriums.

What is still unclear is whether the second wave is manifesting in different demographic and clinical outcomes. Are more young people getting infected and hospitalised, as is currently the case in Brazil, also in the throes of an out-of-control pandemic? Are children more vulnerable this time? Is the virus more infectious and the disease more severe?

There is no clear data to answer some of these questions yet.

But here is what doctors and experts are saying.

Are more younger patients infected?

Since the start of the pandemic till December, those below the age of 45 accounted for 60% of the infections, according to a report on mortality data by the Union health ministry. But this age group was not the one to suffer the most deaths because of the virus. At least 55% of those who died of Covid-19 were aged above 60 years, the report said.

In the current wave, it is not clear whether the age composition of cases and deaths has changed since the central government has not released nationwide data. Data for states is also not publicly available. But a cursory glance at data reported by the media shows no major change in the demographic profile of coronavirus patients.

In Maharashtra, the worst-hit state, those below the age of 40 accounted for 48% of cases between January and March this year, more or less comparable to the age data reported till November 2020. In Karnataka, 47% of those who tested positive for the virus between March 5 to April 5 were between 15 to 45 years, which appears to be similar to last year.

On April 13, Delhi chief minister Arvind Kejriwal said 65% of Covid-19 patients in the city-state are below the age of 45 years. He did not provide comparative data for last year.

Doctors in Delhi hospitals say they are seeing more younger patients compared to last year. “October and November had mostly elderly people, now it is mostly people in their 30s,” said Dr Sumit Ray, head of department for critical care medicine at Holy Family Hospital, a private facility in the capital which was declared a dedicated Covid hospital on April 12. Among these younger patients, he said the most common comorbidity is diabetes, obesity and hypothyroid.

In other states as well, doctors expressed similar concerns. “It is possible that higher vaccination among the elderly is providing them some sort of protection,” Dr Maharishi Desai, an Ahmedabad-based doctor and member of the state’s task force was quoted as saying in The Times of India.

A government official in Chhattisgarh said not only were more younger patients infected, they were more severely infected than last year. “We are seeing more deaths among those who are above 30 years, more deaths of those without comorbidities,” he said, requesting anonymity since he is not authorised to speak to the press.

But the higher number of younger patients reporting to hospitals could simply be a function of a higher number of overall cases this year. India was reporting 10 lakh active cases at the peak of the first wave in September, currently the country has nearly 14 lakh active cases.

Are more children infected?

There has also been concern over whether children are getting infected at a higher rate.

Dr Yogesh Jain, a physician who runs a community hospital in rural Bilaspur, Chhattisgarh, said not only were more children getting infected, but also the infections were more severe in the second wave. “By this I mean that more oxygen is required,” he said.

Nearly 80,000 children from Maharashtra, Chhattisgarh, Uttar Pradesh, Karnataka and Delhi tested positive for the virus between March 1 and April 4, according to data by the Union health ministry. Out of these, more than 60,000 children were infected in Maharashtra in just a month.

But while the absolute numbers for children infected this year might be higher, there is no data to indicate whether the rate of infection among children has gone up.

In the first wave, several cases of children infected with the virus may have been overlooked, say doctors, because they did not show any symptoms. But this may have changed in the second wave.

“Children are definitely more symptomatic now than what we saw in the first wave,” Tanu Singhal, a paediatrician and infectious disease specialist at Mumbai’s Kokilaben Dhirubhai Ambani Hospital, told the Hindustan Times. “The severity of their illness has gone up.”

Some children had to be hospitalised in Mumbai for gastrointestinal infections, breathlessness and fever – all linked to the virus. “Those with gastrointestinal infections had to be put on intravenous fluids,” paediatrician Bakul Parekh told Hindustan Times. “The patients who were breathless required steroids and oxygen support.”

Are the transmission rates higher?

Across India, doctors believe one of the features of the second wave is greater infectiousness of the virus.

“The virus seems to have acquired a greater transferability now,” said Dr SP Kalantri, professor of Medicine and Medical Superintendent at the Mahatma Gandhi Institute of Medical Sciences in Sevagram, Maharashtra.

Compared to last year, Kalantri said that entire families were getting infected from grandparents to parents to children. “The entire spectrum of age groups – from the pediatric to the geriatric population – everyone is getting affected now,” he said.

Dr Yogesh Jain said: “The allegation that [the virus is spreading because] people are careless is complete nonsense... It is predominantly because the virus has changed its form and it is coming with the advantage of being far more infectious. Every other person now has Covid. This was not the case last year.”

In Punjab, an official attributed the greater infectiousness to a new variant of the coronavirus, which was first detected in the United Kingdom and has now been found in 81% of the 401 samples put through genome sequencing in the state.

Similarly, one of the mutations in the variant detected in Maharashtra is associated with higher transmission rates.

Dr Randeep Guleria, director of the All India Institute of Medical Sciences, said during the first wave, a patient could spread the infection to 30 to 40% of their contacts. “This time, it has been observed that 80 to 90% of people who come in contact with a patient turn positive.”

As a result, epidemiologists say the reproduction rate that indicates how fast the infection is spreading is higher in the second wave than in the first. In May 2020, this rate was 1.65, with India reporting 3,000 cases daily. But now as several states are reporting the double the number of cases, the rate has increased to 2, Bhramar Mukherjee, professor of epidemiology at the University of Michigan, pointed out in an interview with the Deccan Herald.

Are infections resulting in more severe illness?

Some doctors have observed differences in the clinical manifestations of the coronavirus disease in the second wave, though these are purely anecdotal accounts at the moment.

Dr Sumit Ray of Holy Family hospital in Delhi said lung damage was occurring earlier among patients – instead of the second week of the illness, it was manifesting in four to five days. “The inflammatory response is earlier,” he said. “Fever is higher and that’s a sign of the inflammatory response, and this seems to be in more numbers of people.”

This necessitates the use of medical oxygen and could perhaps explain why oxygen shortages are being reported in many places, although the shortages could also be a function of the higher number of Covid-19 cases in the second wave compared to the first.

In Gujarat, as more patients get hospitalised, the consumption of medical oxygen has doubled, the Indian Express reported. Dr Janmayjay Nathwani, the medical store and oxygen supply in charge of Rajkot Civil Hospital, told the newspaper: “We have more patients this time, and second, more patients are requiring high-flow nasal oxygen therapy, which requires pumping around 90 litres of oxygen gas per patient per minute as compare to the 15 litres per minute in case of a patient in a normal oxygen bed.”

“One can say, prima facie, people are more unwell this time,” Nathwani said.

However, most experts agreed that it is too early to pin down whether the severity of disease is higher in the second wave. Many, in fact, say the severity of the disease is possibly lower given the lower case fatality rate.

Are fewer deaths taking place?

As the pandemic has progressed, India’s case fatality rate has steadily improved – from 3% in June, to currently 1.3%. But experts cautioned against reading much into this.

“The outcomes in terms of case fatality rate are better,” said Ray, the doctor in Delhi, “but having said that it is a warning if the numbers get overwhelming, which is happening in tier two cities, then deaths will happen because they will not get oxygen or beds.”

“We are on the edge of that in Delhi,” he added. “The systems are getting overwhelmed.”

Mukherjee, the epidemiologist, also warned against claiming a victory by looking at India’s case fatality rate. “If you let the disease spread in an unleashed way, you are looking at a huge number of deaths even with a low case fatality rate like 1.4%,” she explained. She cautioned that more infections would mean more hospitalisations. “The total deaths are a product of infections and fatality rates. And please remember each number is a person.”

Are RT-PCR tests less effective?

Many doctors say in the second wave, patients who tested negative on the RT-PCR test, which is considered the gold standard for Covid-19 diagnosis, are showing symptoms of it nonetheless.

“When we test them again after 48 hours, they test positive,” said Kalantri. “They may have drastic Covid symptoms so it is possible that the RT-PCR is missing such Covid cases.”

This trend was observed by doctors in Gujarat as well, who found the infection in the lungs of patients after putting them through scans.

“We can no longer rely simply on RT-PCR reports,” Dr Krutesh Shah, president of a private doctors’ association in Vadodara told The Times of India. Shah said that a high resolution computed tomography in patients who tested negative later revealed that the infection had spread to the lungs.

However, experts say it is difficult to draw any firm conclusions yet.