Nobel laureate and Stanford professor Michael Levitt has offered the public reassurance during the peak of novel coronavirus outbreak, saying according to his calculations the spread of the virus is slowing down and will come to a halt soon.

Levitt, an American-British-Israeli biophysicist who teaches structural biology at Stanford University and spends much of his time in Tel Aviv, did not discover a treatment or a cure, just did what he does best: crunched the numbers.

The statistics led the professor, who has unexpectedly become a reassuring figure in China, to the conclusion that, contrary to the grim forecasts being branded about, the spread of the virus will come to a halt.

In an interview to Calcalist, Levitt said he might not be an expert in epidemiology, but understands calculations and statistics very well.

The calming messages he sent to his friends in China were translated into Chinese and passed from person to person, making him a popular subject for interviews in the Asian nation. His forecasts turned out to be correct: the number of new cases reported each day started to fall as of February 7. A week later, the mortality rate started falling as well.

Even though he believes the pandemic will run its course, Levitt emphasises his support of all the safety measures currently being taken and the need to adhere to them.

The biophysicist received his Nobel Prize for chemistry in 2013 for “the development of multiscale models for complex chemical systems”, according to the article.

He decided to calculate the rate of infections and mortality rate on request of his wife’s Chinese friends in hope of reaching some conclusions.

His wife Shoshan Brosh is a researcher of Chinese art and a curator for local photographers, meaning the couple splits their time between the US, Israel, and China.

“The rate of infection of the virus in the Hubei province increased by 30% each day – that is a scary statistic. I am not an influenza expert but I can analyse numbers and that is exponential growth,” he was quoted as saying. At this rate, the entire world should have been infected within 90 days, he added.

But then, the trend changed. When Levitt started analysing the data on February 1, Hubei had 1,800 new cases each day and within six days this number reached 4,700, he said. “And then, on February 7, the number of new infections started to drop linearly and did not stop. A week later, the same happened with the number of the deaths. This dramatic change in the curve marked the median point and enabled better prediction of when the pandemic will end. Based on that, I concluded that the situation in all of China will improve within two weeks. And, indeed, now there are very few new infection cases.”

His calculations had been reported every day by various entities, such as the World Health Organisation (WHO). Levitt started sending regular reports to his Chinese friends, and their popularity led to interviews on Chinese television, for example on CNN-equivalent CGTN. Based on the diminishing number of infection cases and deaths, he said, the virus will probably disappear from China by the end of March.

Initially, Levitt said, every coronavirus patient in China infected on average 2.2 people a day – spelling exponential growth that can only lead to disaster. “But then it started dropping, and the number of new daily infections is now close to zero.”

Comparing it to interest rate, he said: “even if the interest rate keeps dropping, you still make money. The sum you invested does not lessen, it just grows more slowly. When discussing diseases, it frightens people a lot because they keep hearing about new cases every day. But the fact that the infection rate is slowing down means the end of the pandemic is near.”

There are several reasons for this, according to Levitt. “In exponential growth models, you assume that new people can be infected every day, because you keep meeting new people. But, if you consider your own social circle, you basically meet the same people every day. You can meet new people on public transportation, for example; but even on the bus, after some time most passengers will either be infected or immune.”

Another reason the infection rate has slowed has to do with the physical distance guidelines. “You don’t hug every person you meet on the street now, and you’ll avoid meeting face to face with someone that has a cold, like we did,” Levitt said. “The more you adhere, the more you can keep infection in check. So, under these circumstances, a carrier will only infect 1.5 people every three days and the rate will keep going down.”

Quarantine makes a difference, according to Levitt, but there are other factors at work. “We know China was under almost complete quarantine, people only left home to do crucial shopping and avoided contact with others. In Wuhan, which had the highest number of infection cases in the Hubei province, everyone had a chance of getting infected, but only 3% caught it,” he explained. “Even on the Diamond Princess (the virus-stricken cruise ship), the infection rate did not top 20%.” Based on these statistics, Levitt said, he concluded that many people are just naturally immune to the virus.

The explosion of cases in Italy is worrying, Levitt said, but he estimates it is a result of a higher percentage of elderly people than in China, France, or Spain. “Furthermore, Italian culture is very warm, and Italians have a very rich social life. For these reasons, it is important to keep people apart and prevent sick people from coming into contact with healthy people.”

China did great work and managed to gain complete control of the virus, Levitt said. “Currently, I am most worried about the US. It must isolate as many people as possible to buy time for preparations. Otherwise, it can end up in a situation where 20,000 infected people will descend on the nearest hospital at the same time and the healthcare system will collapse.”

Israel currently does not have enough cases to provide the data needed to make estimates, Levitt said, but from what he can tell, the Ministry of Health is dealing with the pandemic in a correct, positive way. “The more severe the defensive measures taken, the more they will buy time to prepare for needed treatment and develop a vaccine.”

Levitt avoids making global forecasts. In China, he said, the number of new infections will soon reach zero, and South Korea is past the median point and can already see the end. Regarding the rest of the world, it is still hard to tell, he said. “It will end when all those who are sick will only meet people they have already infected. The goal is not to reach the situation the cruise ship experienced.”