What is the difference between asymptomatic and pre-symptomatic spread of the coronavirus? Experts agree its spread is hard to predict.
Asymptomatic spread takes place when virus is transmitted by people who do not manifest symptoms and will never develop symptoms from their infection. However, infected individuals could still get others sick.
On the other hand, pre-symptomatic spread happens when people who do not look or feel sick pass the virus to others but will eventually develop symptoms later.
Experts say it is not possible to determine if the spread if asymptomatic or pre-symptomatic because both appear normal. However, the pre-symptomatic carriers will manifest Covid-19 symptoms later.
Rare transmission
Studies show that pre-symptomatic spread is more common than asymptomatic spread.
"Detailed contact tracing from Taiwan as well as the first European transmission chain in Germany suggested that true asymptomatics rarely transmit," said Babak Javid, a principal investigator at Tsinghua University School of Medicine in Beijing and an infectious disease consultant at Cambridge University Hospitals.
"However, those (and many other) studies have found that paucisymptomatic transmission can occur, and in particular, in the German study, they found that transmission often appeared to occur before or on the day symptoms first appeared."
Can coronavirus spread without symptoms? "When you speak, sometimes you'll spit a little bit," said Anne Rimoin, an epidemiology professor at UCLA's School of Public Health.
"You'll rub your nose. You'll touch your mouth. You'll rub your eyes. And then you'll touch other surfaces, and then you will be spreading virus if you are infected and shedding" the virus.
According to the US Centers for Disease Control and Prevention, around 40% of coronavirus transmission takes place before people feel sick.
A study published in the journal "Science" revealed about 4 in 5 people with confirmed coronavirus in China likely got the disease through who are not aware they had it.
"These findings explain the rapid geographic spread of (coronavirus) and indicate containment of this virus will be particularly challenging," researchers wrote.
It is reported that people with coronavirus are not aware they have it either because they're asymptomatic, pre-symptomatic, or paucisymptomatic.
CDC data showed that almost half of the 712 people with coronavirus aboard the Diamond Princess cruise ship did not manifest any symptoms when they tested positive.
Moreover, a study from Iceland revealed that 50% of those who tested positive showed no symptoms at the time of testing.
Incubation period
This coronavirus has a lengthy incubation period. This refers to the time between when a person gets infected to when they begin showing symptoms.
