BJP's Kerala unit chief Rajasekharan sworn in as Mizoram Governor

New Delhi, Apr 24: The trajectory of COVID-19 cases could have plateaued and might even fall for some weeks after the lockdown is lifted but India is likely to see a second wave in late July or August with a surge in the number of cases during the monsoon, say scientists.

The timing of the peak will depend on how India is able to control physical distancing and on the level of infection spreads after restrictions are relaxed, they said.

It looks apparent that the trajectory of daily new cases has reached a plateau and eventually it will take a downward fall, maybe for some weeks or even months, Samit Bhattacharya, associate professor at the Department of Mathematics, Shiv Nadar University, said.

Still, we may get a surge of new cases of the same coronavirus and this will be considered a second wave, Bhattacharya explained.

The second epidemic may come back in late July or August in the monsoon, although the peak timing will depend on how we control social distancing during that time, he said.

Rajesh Sundaresan, professor at Bengaluru's Indian Institute of Science (IISc), agreed.

“Once we return to normal activity levels, there is a chance that infection may begin to rise again. China is seeing this to some extent post easing of some restrictions on travel,” Sundaresan, corresponding author of a working paper by researchers at IISc and the Tata Institute of Fundamental Research (TIFR) in Mumbai, said.

On March 25, when the number of coronavirus cases was 618 with 13 deaths, the government announced a nationwide lockdown that was later extended to May 3.

On Friday, the death toll due to COVID-19 rose to 718 and the number of cases to 23,077, according to the Union Health Ministry.

In good news, officials said this week that the doubling rate of cases has slowed down in the period, going from 3.4 days before lockdown to 7.5 days, with 18 states doing better than the national average. The recovery rate has also almost doubled in the last 10 days.

"Looking at the new cases in the past few days, it seems the growth of new daily infection is much slower than earlier. This apparently indicates that we might have reached at the plateau of the growth curve, Bhattacharya said.

He noted that recent studies in China and Europe observed that the infection might relapse in those people who have already recovered from earlier phases.

So, there is no evidence that the earlier infection may help acquire immunity against the second infection. And in that way, the entire population may be vulnerable to the second wave to some extent, said the scientist.

In their study unveiled this week, IISc and TIFR researchers analysed the impact of strategies such as case isolation, home quarantine, social distancing and various post-lockdown restrictions on COVID-19 that might remain in force for some time.

The study modelled on Bengaluru and Mumbai suggests the infection is likely to have a second wave and the public health threat will remain, unless steps are taken to aggressively trace, localise, isolate the cases, and prevent influx of new infections.

The new levels and the peaking times for healthcare demand depend on the levels of infection spreads in each city at the time of relaxation of restrictions, they said.

The lockdown is currently upon us. It has given us valuable time. Let us test, trace, quarantine, isolate, practice better hygiene, search for a vaccine, etc. We should do these anyway, and these are being done. When and how to lift the lockdown is going to be a difficult decision to make, said Sundaresan.

It's clear that it's going to be phased. What our team is focusing on is to come up with tools to help the decision makers assess the public health impact of various choices, he said.

According to the experts, infectious diseases spread via contact between infectious and susceptible people. In the absence of any control measures, an outbreak will grow as long as the average number of people infected by each infectious person is more than one.

Once enough people are immune there will be fewer people susceptible to the infection and the outbreak will die.

However, when an outbreak is brought under control by social distancing and other interventions, it is possible only a small proportion of the population will have been infected and gained immunity, they said.

This means enough susceptible people may remain to fuel a second wave if controls are relaxed and infection is reintroduced.

Until the vaccine comes on the market, we have to remain alert Once sporadic cases occur here and there in the country, we immediately need to implement quarantine or social distancing locally for the people in that region, and also need to perform tests to identify positive cases irrespective of showing symptoms, Bhattacharya explained.

Note that these monsoon months are also flu season in many places of India. So, we should not ignore the early signs of the flu symptoms. Irrespective of symptoms, we need to increase tests in the hotspots to identify people and contain the surge, he said.

Sundaresan added that the timeline for a second wave will depend on a lot of circumstances which may change as the time passes.

Significant testing may have been underway, there may be behavioural changes with people becoming more careful about their hygiene, wearing masks may become more common, etc. All these responses may help restrict the second wave, he said.

A study published in The Lancet journal earlier this month modelled the potential adverse consequences of premature relaxation of interventions, and found it might lead to a second wave of infections.

The finding is critical to governments globally, because it warns against premature relaxation of strict interventions, the researchers said.

While interventions to control the spread of SARS-CoV-2 are in place, countries will need to work toward returning to normalcy; thus, knowledge of the effect of each intervention is urgently required, they said in the study.

According to a recent analysis by the Harvard Chan School of Public Health, the best strategy to ease the critical care burden and loss of life from COVID-19 might be on-again, off-again social distancing.

In the absence of such interventions, surveillance and intermittent distancing may need to be maintained into 2022, which would present a substantial social and economic burden, the researchers wrote.p

India's COVID-19 tally raced past the seven lakh-mark with 22,252 fresh infections on Tuesday, five days after crossing the six lakh post, while the death toll climbed to 20,160 as 467 more people succumbed to the disease, according to the Union health ministry.

With this, the country has recorded over 20,000 cases of the infection for the fifth consecutive day.

India's coronavirus infection caseload stands at 7,19,665, the ministry's data updated at 8 am showed.

With a steady rise, the number of recoveries stands at 4,39,947, while there are 2,59,557 active cases of coronavirus infection in the country.

"Thus, around 61.13 % of patients have recovered so far," an official said.

The total number of confirmed cases also includes foreigners.

Of the 467 deaths reported in the last 24 hours, 204 are from Maharashtra, 61 from Tamil Nadu, 48 from Delhi, 29 from Karnataka, 24 from Uttar Pradesh, 22 from West Bengal, 17 from Gujarat.

Telangana and Haryana reported 11 deaths each; Madhya Pradesh nine; Andhra Pradesh seven; Jammu and Kashmir six; Rajasthan and Punjab five each; Bihar, Kerala and Odisha two each; and Arunachal Pradesh and Jharkhand one each.

New Delhi, Jul 18: The Covid-19 lockdown-led reduction in air pollution levels across five Indian cities, including Delhi and Mumbai, may have prevented about 630 premature deaths, and saved USD 690 million in health costs in the country, according to a new study.

Scientists, including those from the University of Surrey in the UK, assessed the levels of harmful fine particulate matter (PM2.5) from vehicles and other sources in five Indian cities -- Delhi, Mumbai, Kolkata, Chennai and Hyderabad -- since the beginning of the lockdown period.

The study, published in the journal Sustainable Cities and Society, compared these lockdown PM2.5 figures from 25 March up until 11 May, with those from similar periods of the preceding five years, and found that the measure reduced pollution levels in all these places.

According to the scientists, during this period, the levels of these harmful air pollutants reduced by 10 per cent in Mumbai, and by up to 54 per cent in Delhi.

"The percentage reduction for the other cities ranged from 24 to 32 per cent, which was slightly smaller than the measured values for Delhi and Mumbai," the scientists noted in the study.

"While the reduction in PM2.5 pollution may not be surprising, the size of the reduction should make us all take notice of the impact we have been having on the planet," said Prashant Kumar, a co-author of the study from the University of Surrey.

The scientists said these reductions in PM2.5 were comparable to those reported in other cities across the world, such as in Austria's capital Vienna (60 per cent), and Shanghai (42 per cent) in China.

They also calculated the monetary value of the reduced mortality due to air pollution and found that the lowered levels of PM2.5 may have saved 630 people from premature death, and USD 690 million in health costs in India.

Coronavirus India update: State-wise total number of confirmed cases, deaths on July 17

According to the researchers, the present lockdown situation offers observational opportunities regarding potential control systems and regulations for improved urban air quality.

They said an integrated approach might help in understanding the overall impacts of Covid-19 lockdown-style interventions and support the implementation of relevant policy frameworks.

"This is an opportunity for us all to discuss and debate what the 'new normal' should look like - particularly when it comes to the quality of the air we breathe," Kumar said.