Coronavirus study finds 'otherwise healthy' patients can contract virus
TORONTO -- Two new studies focused on the new Chinese coronavirus have revealed that some of the infected were “otherwise healthy” and others showed no symptoms.
Medical journal The Lancet published two studies on Friday based on infected people in Wuhan, acknowledged as the epicentre of the new coronavirus outbreak.
The first report looked at 41 cases of the new virus, labelled 2019-nCov.
“The virus characteristics suggest it’s not quite as serious as SARS, even with today’s Lancet report,” infectious disease specialist Dr. Neil Rau told CTVNews.ca.
“The biggest finding is that some of the patients who were sickened were actually otherwise healthy, they don’t have underlying disease.
“What is definitely getting clearer is that there is a range of spectrum of disease. You can be very severely ill with a SARS-like illness or you can also have very mild disease.”
The new virus appears to cause similar symptoms to severe acute respiratory syndrome (SARS), The Lancet reports.
All 41 patients in the first study were admitted to hospital with pneumonia and most had a fever, cough, and fatigue. Over half of patients also experienced shortness of breath, while headache and diarrhea were rare. Intestinal symptoms such as diarrhea affected only a quarter of SARS patients.
“Another interesting finding in the Lancet study about the severe cases, is that they don’t have what are called upper respiratory tract symptoms, in other words they don’t have the runny nose and the sneezing,” Dr. Rau said.
“They simply have the cough, the shortness of breath and the fever, what we call lower respiratory tract symptoms.
“So there seems to be an absence of upper symptoms, which is maybe good news because a lot of people would be worried if they’ve got the cough, cold, sniffles, that they actually have this.”
The study authors stressed the need to contain infection through “careful surveillance, active contact tracing and vigorous searches for the animal hosts and transmission routes to humans.”
The new coronavirus is believed to have passed from animal to human at a meat market in Wuhan. The 2019-nCoV is most closely related to coronaviruses from Chinese horseshoe bats, according to The Lancet.
So far there have been more than 900 confirmed 2019-nCoV infections, with 26 deaths.
No specific coronavirus antiviral drugs or vaccines have proven effective in humans, according to The Lancet.
Of the 41 patients admitted to hospital in Wuhan between Dec. 16 and Jan. 2, on average, patients were middle-aged, most had visited Huanan market and most patients were men.
“Overall the death rate from this virus seems to be about three per cent, based on the data to date,” Dr. Rau said.
“As we keep finding more and more milder cases, that death rate is going to drop further. Initial estimates of death rates are always higher because we find the sickest patients first.
Rau doesn’t think this new coronavirus “has the ability to turn this into another SARS-type story.”
The Lancet report noted the limits of the study, namely the small number of cases, and called for larger studies in outpatient and community settings to confirm the “full clinical spectrum of disease.”
“It’s still hard to tell the flu from this disease, based on the paper. What we don’t have from that paper is the contagiousness information, when are you most contagious with this disease,” Dr. Rau added.
“This may be a disease more like SARs where you’re most contagious when you have the most severe form of disease, which would also explain why healthcare workers and close household contacts are more at risk.”
THE SECOND STUDY
In the second study, researchers examined a family of seven people who showed an unexplained pneumonia.
Hospital officials identified 2019-nCoV in five members who had recently visited Wuhan and in one other family member who did not travel with them.
Only a child, who was reported to have worn a surgical mask for most of the stay in Wuhan, was not infected.
Another child was infected with 2019-nCoV, but showed no symptoms, suggesting individuals may be able to spread infections in the community without knowing that they are infected.
“The question is whether people without symptoms are actually that contagious or not,” Dr. Rau explained.
None of the family visited food markets or had contact with animals during their stay in Wuhan.
The authors say that the most likely explanation for the family’s infections is that a 65-year-old woman in the family acquired 2019-nCoV while visiting her young relative at the Wuhan hospital, then transmitted it to four other family members during their seven-day trip and to the other family member after flying home to Shenzhen city in Hong Kong.
All six patients remain stable.
“These viruses seem to create more contagious situations when you’re more severely ill. That’s why you don’t get widespread community disease, which is why this may not really take off as a big epidemic or pandemic,” Rau said.
To improve detection of the virus, medical experts have recommended front-line clinics, apart from local centres for disease control, diagnostic kits, frequent hand-washing, covering coughs, surgical masks in public and education campaigns to improve reporting of cases.