Coronavirus patients may be most infectious in first week of symptoms, study finds
- Researchers find viral load highest in first seven days after patients start showing signs of the disease
- Self-collected saliva samples could be safer than throat and nasal swabs taken by medical professionals, they say
The researchers based their assessment on saliva samples from 23 patients confirmed with Covid-19, the disease caused by the coronavirus, at two hospitals in the city.
The results showed that the viral load in the patients – who were all aged between 35 and 75 – was highest during the first seven days after symptom onset and declined gradually after that, according to the paper, published in The Lancet medical journal on Monday.
“The high viral load within the first week of illness suggests that the virus can be transmitted from one person to another easily before the patient is hospitalised,” said Kelvin To Kai-wang, clinical associate professor at the University of Hong Kong’s microbiology department and a co-author of the paper.
In one case, the virus was detected 25 days after the patient showed symptoms.
