Symptomless spread of new coronavirus questioned as outbreak mushrooms

[Karlston]

Outbreak update —

Symptomless spread of new coronavirus questioned as outbreak mushrooms

The main source of infections is most likely people coughing and sneezing.

Enlarge / Information officer wearing protective mask, gloves, and goggle, as prevention of novel coronavirus epidemic, at international arrival gate of Bali Ngurah Rai International Airport in Kuta, Bali, Indonesia on February 4, 2020.

Getty | Nur Photo

The Chinese businesswoman who spread the 2019 novel coronavirus (2019-nCoV) to four colleagues in Germany while reportedly experiencing no symptoms of the infection actually did have symptoms, according to a news report in Science.

 

The woman’s case, published January 30 in The New England Journal of Medicine, was considered the most clearly documented evidence that the novel viral infection could spread silently from asymptomatic people. Public health experts have been particularly anxious about such transmission because it could potentially ease disease spread and negate outbreak control efforts, including screening travelers for symptoms, such as fever.

 

“The fact that asymptomatic persons are potential sources of 2019-nCoV infection may warrant a reassessment of transmission dynamics of the current outbreak,” the authors of the NEJM article concluded.

 

But that conclusion now appears to be based on false information. And, while the new information on these specific cases doesn’t rule out the possibility that asymptomatic spread has occurred or is occurring in other cases, it could help ratchet down fears that asymptomatic spread is driving the now mushrooming outbreak.

 

Experts at the World Health Organization have said repeatedly that even if asymptomatic spread is occurring, it is likely a minor source of infection; coughing and sneezing people are simply much more likely to spread the virus.

 

Moreover, the corrected version of the NEJM article may highlight a more pressing threat to outbreak control—the fact that all five cases in the cluster were mild and unremarkable amid standard cold and flu season.

Missed signs

According to the new report in Science, the businesswoman’s 2019-nCoV infection symptoms went unrecognized because they were mild, masked by over-the-counter medications, and—most notably—the authors of the NEJM article didn’t speak with her before the article was published.

 

The woman, a Shanghai resident who had visited Germany from January 19 to 21, tested positive for 2019-nCoV in China on January 26. The other four cases were identified in Germany by January 28, and the case report appeared in NEJM just two days later.

 

Without direct communication with her prior to the publication, the NEJM article’s authors relied on the accounts of her four sickened colleagues in Germany, who said she didn’t seem sick during her visit.

 

But government health officials in Germany were later able to reach the Shanghai woman by telephone. People privy to details of the call told Science that she said she felt tired, had muscle pains, and took a fever-reducer during her visit.

 

Officials at the Robert Koch Institute (RKI), the German government’s public health agency, have sent a letter to NEJM informing them of the error in the article, according to an RKI spokesperson who spoke with Science.

 

One of the NEJM authors, Michael Hoelscher of the Ludwig-Maximilians University of Munich Medical Center, told Science that they should have been clearer about where they had gotten the information about the woman’s symptoms. “If I was writing this today, I would phrase that differently,” he said.

 

Another author on the article, virologist Christian Drosten of the Charité University Hospital in Berlin, said, “I feel bad about how this went, but I don’t think anybody is at fault here. Apparently, the woman could not be reached at first and people felt this had to be communicated quickly.”

 

Drosten went on to say that—despite the correction—the five cases highlight a potentially dangerous feature of this outbreak—that is, that the infection may not be very dangerous.

 

“There is increasingly the sense that patients may just experience mild cold symptoms, while already shedding the virus,” he said. “Those are not symptoms that lead people to stay at home.”

Circulating unknowns

Indeed, as the outbreak has continued to escalate, experts have noted that the virus appears more contagious than initially thought and that the early outbreak responses focused heavily on identifying the most severe cases, such as those involving pneumonia and respiratory distress. That focus may have potentially missed the spread of mild disease, which may be far more extensive than what is known even now.

 

As of Tuesday morning, there are reports of 20,704 cases worldwide and 427 deaths. According to the World Health Organization’s latest figures, approximately 13.5 percent of cases are severe—though that estimate could change dramatically if many mild cases are missing, which is likely.

 

Of the outbreak cases, a little over 200 are outside of mainland China, scattered in around two dozen countries. Some of those countries have reported limited person-to-person spread, including the United States.

 

The US Centers for Disease Control and Prevention has confirmed 11 cases in the country so far, including nine travel-related cases and two cases of person-to-person transmission within the US among close contacts. The first case identified in the US, a 35-year-old in Washington state, has been released from the hospital and is now in isolation at home. The second identified case, a Chicago woman in her 60s, has been described as doing “quite well” and is primarily being hospitalized for isolation purposes.

 

“The look and feel of the exported cases, I think, really support the argument that there’s a lot of mild disease that is not being detected in China at the moment for the very good reason that they just can’t do it,” Dr. Allison McGeer told Stat News recently. McGeer is an infectious diseases researcher at Toronto’s Mount Sinai Hospital, who helped respond to other outbreaks of emerging coronaviruses, namely those behind SARS (Severe Acute Respiratory Syndrome) and MERS (Middle East Respiratory Syndrome).

 

Public health experts and media are now volleying predictions of how the outbreak will play out—whether it will be contained and fizzle out or become a pandemic (that is, with worldwide spread), and whether it could resurge occasionally or join its four common coronavirus cousins in continually circulating among humans.

 

The answer is still unclear, of course, and, for now, the CDC still considers the risk to the general American public to be low.

 

 

Source: Symptomless spread of new coronavirus questioned as outbreak mushrooms (Ars Technica)  

[x3r0]

One word: carrier. A person who doesn't even realize that he/she has the virus within them, yet somehow, they might not be sick at all, mainly because his/her body immune is higher than usual average persons.