(TMU) — In the two months since the COVID-19 coronavirus outbreak began, numerous studies have been published about the virus. Unfortunately not all of the studies have been peer-reviewed and many of them contradict each other. Even the studies that are peer-reviewed have still been controversial, and it appears that different studies have rendered different results. However, numerous case studies of infected patients have shown that the outbreak may be even more challenging to contain than previously thought.
A case study published this week by Chinese researchers in the journal JAMA has shown that a 20-year-old woman from Wuhan passed the illness on to five of her family members but never became sick herself. To make matters even more confusing, the young woman initially tested negative for the illness before testing positive days later.
A report from the Chinese Centre for Disease Control and Prevention last week suggested that around 1.2% of the officially confirmed cases in China showed no symptoms.
Meanwhile, over half of the people who tested positive on the Diamond Princess cruise ship were asymptomatic. On the cruise ship, 322 of the 621 people tested did not show any symptoms. This is leading many researchers to suggest that there are more asymptomatic cases than we realize, since the numbers counted in the Chinese CDC report did not include people who did not go through the hospitals.
In a briefing earlier this month, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases suggested that many of the asymptomatic cases were not being counted since they weren’t checking themselves into the hospital.
“It’s very clear that the people who are getting caught in that umbrella of reporting are the people that present themselves to a hospital. There’s another whole cohort that is either asymptomatic or minimally symptomatic,” Fauci said.
Doctors believe that the woman from the recent case study had an incubation period of 19 days. Other studies have suggested that the time of incubation could be up to 24 or even 27 days. Due to the complicated nature of the illness and its symptoms, Harvard University epidemiologist Marc Lipsitch recently predicted that the illness would infect between 40% and 70% of the global population.