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Houston, Mar 15: Researchers, studying the novel coronavirus, have found that the time between cases in a chain of transmission is less than a week, and over 10 per cent of patients are infected by someone who has the virus, but does not show symptoms yet, a finding that may help public health officials contain the pandemic.

The study, published in the journal Emerging Infectious Diseases, estimated what's called the serial interval of the coronavirus by measuring the time it takes for symptoms to appear in two people with the virus -- the person who infects another, and the infected second person.

According to the researchers, including those from the University of Texas at Austin, the average serial interval for the novel coronavirus in China was approximately four days.

They said the speed of an epidemic depends on two things -- how many people each case infects, and how long it takes cases to spread.

The first quantity, the scientists said, is called the reproduction number, and the second is the serial interval.

Due to the short serial interval of the disease caused by the coronavirus -- COVID-19 -- they said, emerging outbreaks will grow quickly, and could be difficult to stop.

“Ebola, with a serial interval of several weeks, is much easier to contain than influenza, with a serial interval of only a few days,” said Lauren Ancel Meyers, study co-author from UT Austin.

Meyers explained that public health responders to Ebola outbreaks have much more time to identify and isolate cases before they infect others.

“The data suggest that this coronavirus may spread like the flu. That means we need to move quickly and aggressively to curb the emerging threat,” Meyers added.

In the study, the scientists examined more than 450 infection case reports from 93 cities in China, and found the strongest evidence yet that people without symptoms must be transmitting the virus -- known as pre-symptomatic transmission.

More than one in ten infections were from people who had the virus but did not yet feel sick, the scientists said.

While researchers across the globe had some uncertainty until now about asymptomatic transmission with the coronavirus, the new evidence could provide guidance to public health officials on how to contain the spread of the disease.

“This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted,” Meyers said.

The researchers cautioned that asymptomatic transmission makes containment more difficult.

With hundreds of new cases emerging around the world every day, the scientists said, the data may offer a different picture over time.

They said infection case reports are based on people's memories of where they went and whom they had contact with, and if health officials move quickly to isolate patients, that may also skew the data.

“Our findings are corroborated by instances of silent transmission and rising case counts in hundreds of cities worldwide. This tells us that COVID-19 outbreaks can be elusive and require extreme measures,” Meyers said.

Beijing, Feb 19: The death count from China's new coronavirus epidemic jumped to 2,000 on Wednesday after 132 more people died in Hubei province, the hard-hit epicentre of the outbreak.

In its daily update, the province's health commission also reported 1,693 new cases of people infected with the virus.

This brings the total number of cases in mainland China past 74,000.

Most of the cases are in Hubei, where the virus first emerged in December before spiralling into a nationwide epidemic.

Wednesday's jump in the death count was an increase on Tuesday's figures, although the number of new cases reported in Hubei were the lowest for a week.

A study released by Chinese officials claimed most patients have mild cases of the illness.

Outside of hardest-hit Hubei, which has been effectively locked down to try to contain the virus, the number of new cases has been slowing and China's national health authority has said this is a sign the outbreak is under control.

President Xi Jinping, in a phone call with the British prime minister, said China's measures were achieving "visible progress", according to state media Tuesday.

However, the World Health Organization has cautioned that it was too early to tell if the decline would continue.

On Tuesday the director of a hospital in the central Hubei city of Wuhan became the seventh medical worker to succumb to the COVID-19 illness.

Paris, Jul 20: Two coronavirus vaccine candidates have proven safe for humans and produced strong immune reactions among patients involved in separate clinical trials, doctors said on Monday.

The first trial among more than 1,000 adults in Britain found that the vaccine induced "strong antibody and T cell immune responses" against the novel coronavirus.

A separate trial in China involving more than 500 people showed most had developed widespread antibody immune response.

The studies, published in The Lancet medical journal, constitute a major step on the road towards a COVID-19 vaccine that is effective and safe for widespread use.

The authors of the studies said that they encountered few adverse side-effects from the vaccine candidates.

However, they cautioned that more research was needed, particularly among older adults, who are disproportionately at risk of dying of COVID-19.

Co-author Sarah Gilbert from the University of Oxford said the results "hold promise".

"If our vaccine is effective, it is a promising option as these types of vaccine can be manufactured at large scale."