How coronavirus spread in India — 39 of the first 50 patients came from Italy, Iran, China

India has so far been successful in keeping the COVID-19 infection from spreading within the country, according to details given by the govt.

A volunteer distributes masks to people in Jammu to prevent the spread of coronavirus | Photo: ANI

New Delhi: Most of the coronavirus cases in India originated abroad rather than being transmitted within the country, according to an analysis of official data by ThePrint.

The analysis of the updates issued by the Ministry of Health and Family Welfare shows a majority of those infected since the infection was first detected in India on 30 January had a travel history to countries such as Italy, China and Iran.

Ten of the first 50 cases found positive for the COVID-19 virus in India, until 10 March, did not have a travel history, but came in contact with someone who had travelled abroad. Only one patient so far has been found not to have come in contact with anyone who had travelled abroad.

In total, 23 cases have been routed through Italy, four through Iran, three through China, seven through the US and Dubai combined, and one each through Thailand and Oman.

First wave

The first three cases in India were reported between 30 January and 3 February in Kerala. All three patients had returned from Wuhan, China — the epicentre of what has now been declared a pandemic.

More than 3,400 people who were suspected to have come in contact with the three patients were put in quarantine to contain the outbreak.

The country’s next two cases were reported nearly a month later, on 3 March — one patient in Delhi who had a travel history to Italy, and the second in Hyderabad, who had travelled from Dubai.

The same day, another case was later confirmed as positive for COVID-19 from Jaipur.

Spate of detections

On 4 March, the ministry reported 23 more cases — the highest in a day so far. Fifteen of these were Italian tourists visiting Rajasthan, along with an Indian driver they had hired.

The 23 cases also included the first six ‘secondary cases’ — the Agra residents had been exposed to the Delhi patient detected on 2 March.

Fresh cases have continued to emerge every day since, with people bringing in the virus from Thailand, Iran and Oman.

While the first three patients in Kerala recovered, the state reported five fresh COVID-19 cases on 8 March — three members of the same family and two of their relatives. Three of them had a travel history to Italy, while the other two contracted the disease from them in India.

Five more cases were reported on 9 March — one each from Kerala, Delhi, Uttar Pradesh, Jammu and Punjab. The Kerala and Punjab patients had travel history to Italy, while the Jammu patient had travel history to Iran. The other two had caught the infection within India.

Then, on 10 March, six new cases were reported in India, taking the total number of infected patients to 50. Three of these cases were reported from Bengaluru and the patients had recently returned to India from the US via Dubai. One more case was detected in Bengaluru, with the patient reporting a travel history to the US and back via Heathrow, London. Two positive cases were reported in Pune with travel history to Dubai.

Ten new cases of COVID-19 were reported on 11 March, and another 13 Thursday, bringing the total count to 73 by 12 March.

However, starting 11 March, the ministry has stopped providing details about how these cases originated.

India doing well in stopping secondary cases

Speaking to ThePrint, Dr Ram Rup Sarkar from CSIR-National Chemical Laboratory, who works on mathematical modelling and biological systems, said compared to how the infection has spread in other countries, India is doing much better in arresting secondary cases.

“Our quarantine programmes have vastly helped contain the spread,” Sarkar said.

To understand how the disease is spreading and what needs to be done to contain it, he explained, the progression of cases needs to be observed over a number of days.

“We call this the basic reproduction ratio, which is the number of secondary infections from a particular primary infection,” Sarkar said.

In China, within the first few days, the infections went from a few hundred cases to thousands. Similarly in Italy, over a span of two weeks, the number of cases reached over 10,000.

“This is an epidemic situation, where the number of secondary infections keep going higher and higher. At that point, you need to quarantine people,” Sarkar explained.

“In India, we were able to observe what was happening in China and get an early start on putting in measures to quarantine patients,” he said.

How a particular infection might spread can be predicted from past experiences with some diseases, but very little is known about the novel coronavirus. For example, it is yet to be confirmed if the onset of summer will stop the spread of COVID-19 or worsen it, Sarkar said.