What asymptomatic and presymptomatic carriers mean for the COVID-19 pandemic
As communities begin to reopen amid the COVID-19 pandemic, public officials, medical professionals and health experts ask that if community members feel sick that they stay home in order to prevent spreading the virus.
However, as more is discovered about the SAR-CoV-2 virus, which causes the COVID-19 disease, it has become clear that not everyone who is infectious shows symptoms.
“A big challenge that we have with COVID-19 is that it has a long incubation period, from the time when an individual is exposed to the virus to when they eventually develop symptoms,” said Dr. Haase, SDI’s Medical Director.
Even if a patient isn’t showing symptoms, they may still be infectious and could be unknowingly spreading the virus. Recent studies show that a substantial portion of individuals infected with COVID-19 are asymptomatic, or experience no symptoms. This means the only way to truly know who is and isn’t infected is through community-wide, accurate testing.
“Some of those people will stay asymptomatic,” Dr. Haase said. “They will never develop symptoms. They will just be a carrier of the virus, some of these people we recognize as ‘super spreaders.’ They can go out into a community and spread the virus far and wide because they don’t know that they’re sick, so they don’t have any reason to be cautious.”
Presymptomatic describes the period of time in which an individual is infected with COVID-19 and is highly contagious, but hasn’t shown signs of symptoms yet.
“We talk about asymptomatic and presymptomatic, but we can’t really know who is who until after that person has been infected long enough to understand whether or not they’re going to develop symptoms,” Dr. Haase said. “The terms are very useful for researchers, but they’re not very helpful when it comes to changing the curve because the individuals that are already infected and asymptomatic, whether or not they develop new symptoms, they’re a danger, and they need to be identified.”
The only way to identify asymptomatic patients is through viral RT-PCR RNA testing, he said. This is why it is important to test everyone, not just those who show symptoms.
In response to this, SDI’s comprehensive approach to the COVID-19 pandemic, — which includes testing, tracking, treating, and isolating — recommends testing everyone within a community.
“You need to start somewhere,” said Oz Mohiuddin, SDI’s CEO. “You need to baseline that patient population to say whether they are infected or not … The most amount of spread happens at the asymptomatic and presymptomatic level. The data is clearly showing that this is the approach. We believe it is the most prudent approach moving forward.”