The virus came to be named as SARS-CoV-2, and the infection was termed coronavirus disease, or Covid-19.

In the three years since, India has seen three distinct waves of the pandemic — the first driven by the original virus in 2020, a sharp peak driven by the deadly Delta variant in April-May 2021, and the third by the less lethal but more contagious Omicron variant in January 2022. More than 4.4 crore Covid-19 infections and 5.3 lakh deaths have been reported across the country so far.

At the same time, more than 220 crore doses of vaccines have been administered, with over 90% of the population over the age of 12 years having received at least two doses.

Around the world, the virus has caused more than 752 million confirmed infections and 6.8 million deaths, according to the World Health Organization (WHO) data.

India’s three Covid waves

The first three cases of Covid-19 in India were reported in medical students who returned to Kerala from Wuhan. They did not transmit the infection to contacts, and no new case was reported for over a month. The next set of infections was detected in early March, causing local spread and clusters.

The Centre initially brought in measures like screening international passengers for fever. On March 11, 2020, the WHO declared Covid-19 a pandemic.

Harsher measures then kicked in. All international flights into India were suspended by March 23. The government announced a 21-day lockdown, which was extended thrice. All non-essential work was halted during the lockdown.

The number of cases started increasing in June, driven by the original variant, and peaked in September when over 6.4 lakh cases and over 8,000 deaths were recorded in a week. This wave also saw hospitals stopping routine outpatient procedures in order to keep beds vacant for Covid-19 patients. Even patients with mild symptoms were admitted to hospitals.

Not knowing how to treat the new infection, doctors used a variety of medications, including the anti-malarial medicine hydroxychloroquine and antibiotics like azithromycin. Some doctors also used the anti-parasitic medicine ivermectin. In various trials later, none of these therapies could be shown as effective.

What did work was high-flow oxygen to improve breathing in patients whose lungs were affected, and steroids like dexamethasone for those whose immune system went into overdrive and started attacking organs.

The second wave in April-May 2021 was brutal, with a huge spike in cases and deaths reported over a short period. The sheer numbers overwhelmed health systems, leading to a shortage of beds, oxygen, and healthcare professionals.

The government was criticised for having declared a premature victory over Covid-19, and for allowing political rallies in West Bengal ahead of Assembly elections and events like the Maha Kumbh in Haridwar, which was attended by over 9 million people.

With the Delta variant going deep into the lungs and causing severe pneumonia, more and more patients — even those in their 20s and 30s — ended up in hospitals in need of oxygen. This led to a spike in demand, and the government diverted industrial supplies of oxygen to hospitals. The increasing burden on healthcare structures also meant that by April, the government allowed home isolation of patients with mild symptoms.

The Delta wave also saw many developing the deadly fungal infection mucormycosis after a bout of Covid-19.

The increase in infections was seen despite India rolling out a vaccination drive in January 2021 — beginning with healthcare workers, frontline workers, and the elderly. Over 5.5 crore doses had been administered by the end of March 2021.

At its peak in May, the second wave saw 27.4 lakh cases and over 28,900 deaths in a week. The Health Minister was changed after this, with Mansukh Mandaviya taking over from Dr Harsh Vardhan.

The third wave, driven by the Omicron variant, was smaller both in terms of the number of cases and hospitalisations and deaths. At the peak in mid-January 2022, there were 21 lakh cases with around 7,800 deaths.

The Omicron variant, though spreading faster than Delta, mostly led to upper respiratory tract symptoms. After the wave subsided by February, most restrictions were eased.

By March, international flights to the country had resumed and the Disaster Management Act, invoked to empower the government to implement restrictions and control measures, was revoked.

Impact of the lockdown

On March 24, 2020, with less than 600 confirmed Covid cases, Prime Minister Narendra Modi announced a nationwide lockdown. This prompted a massive reverse migration — workers, left with no livelihood and with modes of transport shut, made their way back home on foot.

Scientists have since said that the lockdown was unlikely to stop the spread of the infection, but it might have helped in “flattening the curve” and giving time to scale up health infrastructure.

On March 26, 2020, the government announced a stimulus package of Rs 1,70,000 crore to provide food security, direct cash transfers, and cooking gas to those affected by the lockdowns.

“The government’s sudden enforcement of the lockdown seemed hastily prepared and immediately disadvantaged already vulnerable populations. Reports suggest that the government’s efforts to provide financial support and a measure of food security to ease these pressures will be insufficient to meet demand. But better planning and communication could have helped avert this crisis,” The Lancet said in an April 2020 editorial.

The crisis of oxygen supply

The sudden increase in the number of patients needing oxygen during the Delta-variant driven wave quickly led to a nationwide oxygen crisis.

The daily liquid medical oxygen supply was increased from 1,292 MT in February to 8,593 MT by April. A total of 10,250 MT of liquid medical oxygen was allocated to the states. This was done by enhancement of production in steel and other plants capable of generating oxygen. Restrictions were also imposed on industrial use of oxygen.

“The government failed to manage the even distribution of oxygen in the states and amidst the skyrocketing demand, the government could not maintain a steady flow of oxygen leading to an unprecedented medical crisis,” a Parliamentary panel noted.

The shortage of oxygen also saw a blame game between some state governments and the Centre.

Testing, genome sequencing

Testing in India began with one laboratory at the National Institute of Virology in Pune in January 2020. By March, the government allowed private laboratories to start conducting tests for Covid-19, and capping the price at Rs 4,500. Now, laboratories even in remote areas are equipped to conduct RT- PCR tests for the virus.

India has also developed cheaper indigenous kits and started using TB diagnostic machines like CBNAAT and TrueNat for Covid-19 detection. At present, there are 3,394 laboratories across the country that can conduct the test, which costs around Rs 300 to Rs 400. The government has also approved the use of rapid antigen tests and home kits.

In addition, the government has scaled up genome sequencing through the Indian SARS-CoV-2 Consortium on Genomics (INSACOG), which is now a network of 52 laboratories across the country. India has already submitted over 2.25 lakh genome sequences of the virus to the international database.

Nationwide vaccination drive

India rolled out Covid-19 vaccination on January 16, 2021, with the Indian version of the Oxford/AstraZeneca vaccine Covishield, and the then still-under-trial Covaxin. The vaccination of healthcare workers began in January and frontline workers in February. Vaccination for people above the age of 60 and those above the age of 45 with comorbidities began in March 2021. By April, the vaccination drive was extended to all above the age of 45 years.

Even as the Centre opened up the vaccination drive for all adults in May, it said the cost would have to be borne by the states or by private players. By June, the decision was reversed and centralised procurement started again.

In September 2021, a record 2.5 crore people were immunised on the Prime Minister’s birthday.

The administration of a third booster dose and vaccination in children over the age of 12 years started in 2022. At present, 97% of the eligible people have received their first dose and 90% their second dose. The coverage of the third precaution dose has remained low, with around 27% of the adults having received it so far, according to data shared by the Health Ministry in December.