The current cluster of novel coronavirus cases in Britain may have included another infection, a World Health Organization official says.
To date, three members of an extended family have tested positive for the new virus, which is a cousin of the SARS coronavirus. One of the three died earlier this week.
But officials investigating how the virus moved from one member of the family to the next suspect another relative may have contracted the virus and may even have spread it to the third confirmed case in the cluster. This fourth family member had a respiratory illness but was not tested until after she recovered, at which point the test came back negative.
Dr. Anthony Mounts, the WHO's point person for the new coronavirus outbreak, says the U.K. cluster adds slightly to the WHO's concern over the virus, but in the main serves to confirm some things the organization has already strongly suspected.
Those are: In some circumstances, person-to-person spread can occur, though so far, it appears those chains of infection has been short. And while the first few cases spotted all involved severe illness, some infections can produce mild symptoms only.
The WHO revised its new coronavirus case definition this week to remind doctors not to automatically rule out people with mild symptoms when they look for possible cases. And Mounts says the organization's recommendations on how to do surveillance for cases will also be updated.
Mild infections are a mixed blessing. Obviously everyone would hope the virus didn't always cause severe disease. But people suffering only mild infections may be more likely to spread the virus, if the virus transmits easily.
That's because people sick enough to be in hospital ICUs mainly encounter health-care workers protected by masks, but people with mild respiratory infections generally go about their daily life. And mild infections are much harder to spot, especially when they occur during cold and flu season.
The third confirmed case in this cluster had only mild symptoms and has since recovered. "The fact that she had such a mild illness really does raise our concerns about what we might be missing," Mounts admits.