(Yicai Global) March 16 -- Testing positive for the novel coronavirus after surviving an initial bout does not mean that you will get it again, according to a recent study on monkeys by a scientist from the Institute of Laboratory Animal Science at the Chinese Academy of Medical Sciences.
Rhesus macaques that were recovering from a Covid-19 infection and which were re-exposed to the same strain of virus once their symptoms had abated showed no recurrence of the disease, according to a March 14 paper by Qin Chuan published on bioRxiv, an open access non-peer reviewed repository for the biological sciences.
That demonstrates that the primary infection can protect from subsequent exposures and has important implications for the prognosis of the disease and vaccine design, according to the paper Reinfection Could Not Occur in SARS-CoV-2 Infected Rhesus Macaques.
Though the study targeted monkeys, it has significant ramifications for China's 80,000-plus coronavirus patients. Discharged individuals who later tested positive greatly complicated disease prevention and control efforts and gave rise to many additional costs.
Testing nucleic acid positive doesn't mean a patient is carrying the live virus and has relapsed, several experts have previously told Yicai Global. Gradually, the virus segments that remain in recovering patients will clear.
"At the moment we don't have any patients who have relapsed," a medical practitioner said. "Some patients tested positive because they haven't recovered. Others had recovered but they still carried the viral nucleic acid in their bodies, which is detectable sometimes but undetectable other times."
The accuracy of nucleic acid testing depends not only on the sensitivity and specificity of the diagnostic reagent, but also on the handling by medical personnel and the amount of virus in the patient, he added.
"Sometimes the virus exists in samples taken from a patient's throat, but sometimes it doesn't. That is why some people who have contracted the disease test negative," the clinical expert said. "Moreover, mistakes made when taking samples can lead to them containing no virus and thus giving a false negative result."
Patients recovering from the disease, however, do not necessarily need any medical treatment even if they test positive, he added.
Editors: Chen Juan, Kim Taylor