The novel viral infection came to light after China reported a cluster of pneumonia cases with no known cause from Wuhan on December 31, 2019. By the end of January 2020, nearly 10,000 cases had been reported, including more than 100 cases in 19 other countries.
WHO raised its highest level of alert and termed the infection a Public Health Emergency of International Concern, a designation that remained in place for over three years.
Why did the WHO declare Covid-19 a pandemic?
SARS-CoV-2 was a novel virus about which very little was known in the initial days. Later, as many patients reached hospitals with pneumonia and in need of oxygen support, doctors and researchers discovered that the infection put the immune system into overdrive, leading to a cytokine storm when immune cells started attacking the patient’s own organs. This tended to happen more in the elderly, and in those with existing comorbidities like diabetes.
“There are three conditions for declaring a disease a public health emergency. One, it is spreading across several countries. Two, it is leading to serious illness, hospitalisations, and deaths. Three, serious stress on health systems because of the disease. Covid-19 fulfilled all three conditions in 2020 and 2021,” Dr K Srinath Reddy, Distinguished Professor, Public Health Foundation of India, and former member of India’s Covid-19 task force, said.
India has reported 4.43 crore cases and 5.3 lakh deaths due to Covid-19 so far. Globally, the number of infections has crossed 76.5 crore, and caused 69.2 lakh deaths.
And why has the WHO removed the designation now?
Over the last three years, doctors and researchers have figured out a lot — methods of transmission; who are at highest risk of severe disease and death; better, cheaper, and point-of-care diagnostics; a treatment protocol that works; medicines to prevent viral replication that can help in reducing severity of the disease; and most importantly, vaccines that can prevent severe disease.
Governments have strengthened healthcare systems and rolled out vaccination drives. In India, more than 90% of people above the age of 12 years have received their two primary doses. Since many were infected and vaccinated, the population has developed a ‘hybrid immunity’ that has been shown to offer better protection against future severe disease.
“Omicron was more infectious (transmitting quickly) but less virulent (causing milder disease). This was because the virus changed to become less dangerous but also because people acquired immunity,” Dr Reddy said.
“Health systems are no longer stressed; focus is back on non-Covid conditions that were neglected during 2020 and 2021. So, for a good part of 2022 and now 2023 Covid-19 did not satisfy the three conditions for a disease to be a public health emergency,” he said.
How did the pandemic unfold in India?
India witnessed three distinct waves of Covid-19 infections. The first wave, from mid-2020 to around September of that year, was caused by the original variant. It was when doctors were figuring our treatments, and the guidelines changed frequently. Testing increased from just one laboratory in Pune to hundreds of centres across the country.
The second wave in April-May 2021 saw a large number of cases and deaths over a short period. The surge was driven by the Delta variant that led to deep lung impact and resulted in hospitals overflowing with people in need of oxygen and ventilator support. There was a shortage of medical oxygen.
The third wave, driven by the Omicron variant, was smaller both in terms of number of cases and hospitalisations and deaths. 21 lakh cases reported in a week at the peak in mid-January 2022, but deaths were only about 7,800.
India has since seen ups and downs in the number of cases, but no wave across the country. Hospitals and health systems have been kept ready. Testing and genomic sequencing have been carried out continuously to monitor the situation.
Cases increased through April, with over 12,000 cases reported in a day. The numbers have, however, started going down again — only 3,611 new cases were reported across the country on Friday.
How will the WHO declaration change disease management?
There are no lockdowns; international travel, restaurants, and cinemas are normal; and containment and control measures haven’t been needed for some time now. So, not much will change on ground with the WHO declaration.
“At the moment, no practical impact to the common man, but surveillance may stop or reduce greatly. We do need to continue the surveillance. Perhaps an intermediate path,” Dr Anurag Agarwal, head of the WHO’s committee tracking the evolution of SARS-CoV-2, and former head of the country’s Covid-19 genomic sequencing consortium, said.
There exists a possibility, however tiny, that the virus may mutate to cause more severe disease. “It is very unlikely however”, Dr Agarwal said, “and most likely it will just circulate like another respiratory virus.” However, because there is always a chance, “some surveillance should continue”, he said. “Perhaps limited surveillance, for example of sewage, reservoirs.”
Dr Reddy agreed: “We need to look out only for variants that can be dangerous and disruptive. The focus of surveillance has to be on hospitalised cases and the variants causing it. Community level surveillance can be through waste-water and detection of clusters.”
Also, he said, immunity was declining in the population. Although universal vaccination is no longer required, as immunity declines it may be considered in the old and comorbid, Dr Reddy said. Those at high risk should wear masks in crowded and poorly ventilated spaces as a precaution, he said.
SARS-CoV-2 was a novel virus about which very little was known in the initial days. (Representational) 
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