Covid-19 cases in the national capital have been on a steady upward march since October, touching a daily high of over 8,500 on November 11 and the seven-day average of daily growth touching 0.8% when the same figure for India is 0.4%. In the process, the Delhi government found itself at the receiving end of the wrath of the Supreme Court, which demanded a status report from Delhi, Gujarat, Maharashtra and Assam on the spike in cases.
Gujarat’s daily cases have been hovering around 1,500 after a dip in October, while Rajasthan and Haryana saw a steady rise in November. The 7-day average test positivity rate — meaning, percentage of tests that are positive, which indicates a high number of positive cases or low testing — in states like Delhi, Himachal Pradesh and Rajasthan are well above the national average of 3.5%.
Simultaneously, the southern states, which accounted for close to 30% of cases in India in July, have been seeing a steady decline in active cases. On Monday, the Union Ministry of Health pointed out that the number of active cases in Karnataka, for instance, dropped by over 43,000 in November, by 28,500 in Kerala and by 15,000 in Tamil Nadu and Andhra Pradesh compared with October. Karnataka, which had seen daily cases of over 10,000 in early October, reported less than 1,000 cases for the first time in five months on December 1. Tamil Nadu has been seeing a similar dip in cases as well as test positivity rate and average growth.
Conversations with a range of experts in public health and epidemiology reveal a consensus that a surge was broadly expected in the north with the onset of winter, coinciding with the festive season. They also agree that while the plateau in the southern states — barring Kerala — is a relief, new spikes cannot be ruled out and surveillance and constant vigilance need to continue. However, the big metropolises are likely to see slower rate of growth of infection.
“That the cases would increase (in the national capital) was broadly expected as respiratory diseases, such as influenza, tend to spike during winter as people stay close together in less ventilated environments. Gatherings during the festive season would also have led to a rise in infections,” says Gautam Menon, professor of physics and biology at Ashoka University and a researcher in modelling infectious diseases. Veteran epidemiologist Dr Jayaprakash Muliyil suspects micro networks in the form of indoor gatherings during the festival season might have pushed up cases in the national capital region (NCR). “You don’t suspect your own kith and kin to have Covid, even though they might have been meeting others. It’s human tolerance at play; it’s not easy to be continuously careful.”
Muliyil says the nature of any pandemic is such that it will continue till a particular percentage of people has been infected, unless there is a vaccine before that. “Once that point is reached, brakes will automatically be applied to the spread, because that’s what nature has destined,” he says. He rejects the use of the phrases second and third wave, saying it’s all part of the same wave. Menon agrees. “I’m not sure the ‘wave’ terminology is appropriate here, since the numbers of cases never dropped to low levels in the period in between, which is what a wave might suggest. The levels of testing have also changed considerably between earlier this year and now and increased testing might account for some part of the increase in cases as also the changing mix of RT-PCR and RAT tests,” says Menon, cautioning that disentangling these effects is not easy.
“One thing common to Tamil Nadu Karnataka and AP is that they follow the syndromic approach, where whoever has COVID-19 symptoms is prioritised for testing”
Health economist Rijo M John, who has been analysing the numbers daily since the beginning of the pandemic in India, says that many districts in NCR, Rajasthan and Haryana have been seeing a rise in cases, as have Himachal Pradesh and Gujarat. The hill state, which was among the last few states to allow tourists without Covid test results, now has one of the highest test positivity rates in the country. But John, an adjunct professor at Rajagiri College of Social Sciences, Kochi, says he is more intrigued by the fact that if one looks at cases as a percentage of the population, it is between 1% and 2% in south India and Maharashtra while in northern and central India, it is less than 0.5% , while the Indian average is 0.7%. “Are we saying that the disease has spread deeper only in south India? That’s highly improbable,” he says. It is even more puzzling because Uttar Pradesh and Bihar are doing a bulk of the testing in India — close to a quarter of the daily testing. Possible explanations, he says, could be that surveillance is inadequate, tests are ineffective or are not being deployed where they are needed the most.
On the dip in cases, Tamil Nadu health secretary J Radhakrishnan says the state adopted an aggressive, focused testing strategy on the advice of medical experts. “People used to make fun, saying Tamil Nadu will get 5,000-6,000 cases every day. But after 6-8 weeks of this, our measures began showing results, with cases falling,” says Radhakrishnan.
In the case of Karnataka, the recent decline is the cumulative effect of testing, tracking, treating and reasonably good compliance of the public overall, says Dr MK Sudarshan, chairperson of the State Covid-19 Technical Advisory Committee. A state-wide survey in September indicated that 30% of the population was infected which he says is likely to have gone up to 50% by now.
Dr Giridhar R Babu, epidemiologist and professor at Public Health Foundation of India and a member of ICMR and Karnataka task forces on Covid, says Karnataka, Andhra Pradesh and Tamil Nadu took a syndrome-based approach to testing. “This means whoever showed Covid symptoms was prioritised for testing. If you are not testing people with symptoms and are randomly testing people, your goal is to simply increase the number of tests you are testing.”
Experts are, however, cautious about predicting new surges. In Karnataka, the technical advisory committee for Covid-19 warns of a second wave in January-February and says this can be recognised early through close monitoring of the seven day average growth rate and reproduction number at the state and district levels. “Areas with higher population will have higher risks. We want to be vigilant in the cold months,” says Sudarshan.
In Tamil Nadu, Radhakrishnan says the state is concerned about people gathering for weddings, funerals, religious events and political rallies. “We are constantly analysing clusters.” Despite the low numbers in the last couple of weeks, he says there is no room for complacency.
“As people travel, they can spark new infections in the places they go. Sero-surveys suggest that while a good fraction of the city population has been infected already, there are more who could get potentially infected although the growth rate will be slow”
In Kerala, which was lauded for its handling of the pandemic early on but now reports the most number of daily cases following a surge after Onam, health officials are worried about the impact of the upcoming local body elections. “The number of positive cases in a day are likely to go up, even up to five figures, because the election campaigning groups don’t pay much heed to scientific advice,” says state nodal health officer Dr Amar Fettle. He says the pandemic is still under control in the state, attributing the daily numbers to a responsive public who come forward for testing and a dynamic, localised testing strategy which is revised every day. Once the numbers go up after the elections, says Fettle, it will be hard to bring them down. “Like petrol prices,” he adds wryly.
The Delhi government, responding to strictures from SC and the Centre, has increased testing and capped the price of RT-PCR tests.
By the end of November, the positivity rate had halved from the middle of the month.
Since there are still many unknowns about the Covid pandemic, even after living with it for nearly a year, it is difficult to make predictions about trends, says public policy and health systems expert Dr Chandrakant Lahariya. “As long as the virus is around and there is a susceptible population, there will be cases in the community.” A spike, he says, depends on multiple external factors, such as whether people adopt Covid-appropriate behaviour and if there are social and cultural events. What can help, he adds, are strengthening surveillance, monitoring data regularly and adapting strategies to local conditions. The biggest challenge in preventing spikes in the days ahead might well be a pandemic weary population. “It’s a constant struggle to convert awareness into change of behaviour. We feel there is one set of people who are concerned and compliant and another set of people who feel nothing may happen,” says Radhakrishnan.