Is Corona Virus Contagious? An Update for Dental Professionals

A deadly new coronavirus has now reached at least 13 countries. With every day new cases being reported, there are currently 2794 confirmed cases of the virus, while tens of thousands of people are being kept under medical supervision around the world. Eighty-one people have died with the virus, according to latest reports.

More deaths are predicted to follow. The virus can spread before symptoms show, China’s health minister Ma Xiaowei, which means it will be more difficult to limit transmission between people.

There are confirmed cases of the virus across Asia, and in the US, Australia and Europe. Confirmed cases have also been reported in mainland China, Hong Kong, Macau, Thailand, the US, Australia, Japan, Malaysia, Singapore, Taiwan, France, South Korea, Vietnam, Canada and Nepal. All of the recorded deaths have so far been in Hubei province.

Growing outbreak

The scale of the outbreak will depend on how quickly and easily the virus is passed between people. It appears that, on average, each person infected with the virus passes it to between 1.5 and 3.5 other people, according to an analysis by Natsuko Imai and her colleagues at Imperial College London.

But there is still much we don’t know about the virus, and some researchers suggest that it could spread more quickly than estimated. One study, estimates that each person with the virus can pass it to between 3 and 5 other people. The work, by Shi Zhao at the Chinese University of Hong Kong and his colleagues suggests that the virus is much more contagious than originally thought.

Thompson’s estimate was calculated based on the assumption that the virus isn’t contagious until symptoms show and this no longer seems to be the case. “If the virus is able to spread before symptoms show, that could certainly explain why the virus is spreading quicker that SARS,” says Thompson.

The US Centers for Disease Control and Prevention (CDC) cautions that, although only five cases have been reported in the US so far, person-to-person spread of the virus in the country is “likely to occur to some extent”.

So far, the new virus seems to have a lower fatality rate. Based on the number of reported cases and deaths, the rate appears to be around 2.8 per cent, compared with a 9.6 per cent rate for SARS. But it is too soon to be sure just how dangerous the virus is. We are still in the early days of the outbreak, says Thompson.

The virus is spreading more quickly than SARS. The SARS outbreak was over by 2004, there have been no reported cases since then. Health agencies brought the virus under control by isolating people with the virus, and screening air travel passengers. Such measures will be more difficult with a virus that can be spread before symptoms appear.

There is also always a chance that the virus could mutate to become more contagious or deadly. However, there is no evidence yet that the virus has mutated within people, and the World Health Organization (WHO) told a press conference last week that the virus appears to be stable.

So, how worried should we be?

The WHO is still holding off from declaring a public health emergency of international concern, although the organisation says the risk of the virus is “very high in China, high at the regional level and high at the global level”.

The CDC describes the outbreak as a “very serious public health threat”. “I am pretty worried about the current situation,” says Thompson. He expects the WHO to officially declare a public health emergency if and when the virus begins to spread between people outside China. “I’m definitely nervous about it,” he says.

Slowing the spread

In the meantime, health authorities in China have undertaken unprecedented measures in an attempt to control the spread of the virus. Wuhan, where the outbreak began, has been placed on lockdown – public transport has been shut down, the airport is closed, and the use of personal motor vehicles has been banned. Immigration services in the city have been suspended in Wuhan. Several other cities have also been placed in lockdown, affecting tens of millions of residents.

-Courtesy by NewScientist