Asymptomatic carriers of the novel coronavirus could be more infectious before the onset of symptoms, a study claims.
According to the research:
“We observed the highest viral load in throat swabs at the time of symptom onset, and inferred that infectiousness peaked on or before symptom onset.”
Viral shedding begins days before onset of symptoms
The researchers studied 94 patients who were confirmed to have been COVID-19 positive and had a “separate sample of 77 infector-infectee transmission pairs.”
The researchers noted that “that viral shedding may begin two to three days before the appearance of the first symptoms. After symptom onset, viral loads decreased monotonically.”
This meant that even days before the first symptoms show, viral shedding, or the likelihood of transmitting the virus, has already taken its course. The virus given off is lessened as soon as those infected start showing symptoms.
How will this change public health policies?
The research says that contact tracing and isolation could not guarantee absolute success in controlling the spread of the virus. This is especially the case if “more than 30% of transmission occurred” before the symptoms were first observed.
“Disease control measures should be adjusted,” the researchers urged.
This is because people who were thought healthy but eventually tested positive could have already infected others without their knowledge.
The study suggests that the criteria for contact tracing should be more inclusive to cover transmission events two to three days before the onset of the disease’s symptoms.
It will mean that health investigators may have to trace the contacts of a patient even from when they still felt healthy.
Concerns about vaccine mass production
While the world economy appears to go backward, the medical industry moves forward at a faster pace.
Laboratories all over the world are racing towards a vaccine. While it can be eventually found, the next concern will be how the vaccine can be mass-produced.
Kathleen Sebelius, former Health and Human Services Secretary, said:
“The shortages that have been happening right now are going to be even more dominant once we get treatments and vaccines. […] There is never going to be enough vaccine at the front end to vaccinate everybody, and the decisions about where the vaccine goes and who gets it first need to happen right now.”
In the meantime, the U.S. urged its people to wear face-masks when going out even if they feel healthy. Social distancing protocols are encouraged. But as much as people can, they are asked to stay home.