Coronavirus Spreading Asymptomatically Is 'Very Rare,' World Health Organization Says

More progress appears to be made about the ongoing coronavirus pandemic, including some information about how the virus itself is spread. Previous studies have indicated that a high number of those who'd tested positive were asymptomatic, which helped change the course on mask-wearing guidelines. New evidence suggests that these carriers may not be spreading the disease. Dr. Maria Van Kerkhove, head of WHO's emerging diseases and zoonosis unit, explained the findings to MSNBC on Monday.

"From the data we have, it still seems to be rare that an asymptomatic person actually transmits onward to a secondary individual," Van Kerkhove said at a news briefing from the WHO's headquarters in Geneva. "We have a number of reports from countries who are doing very detailed contact tracing. They're following asymptomatic cases. They're following contacts. And they're not finding secondary transmission onward. It's very rare."

Though Kerkhove, and the WHO as a whole, stressed that the virus could be transmitted via those without symptoms, it was not the main way that it's been spread over the past several months. However, Van Kerkhove stressed that more research and data would need to be collected before they could "truly answer" these questions. "What we really want to be focused on is following the symptomatic cases," she continued. "If we actually followed all of the symptomatic cases, isolated those cases, followed the contacts and quarantined those contacts, we would drastically reduce" the spread.

One of the more striking studies was done in Iceland in March, which tested nearly 18,000 of its citizens, or about 5 percent of its total population. Of those tests, half were conducted by the biopharma company deCODE, which employed a screening program that "accepts everybody who is not showing symptoms and not currently in quarantine," according to Iceland's Directorate of Health. Of those 9,000 tests, 1 percent came back positive. However, half of that 1 percent showed no symptoms typically associated with coronavirus.

Given the numerous symptoms, not to mention the varying ways its impacted those who've had it, there's also emerging evidence that points to it possibly being a disease that affects the blood vessels directly. In a recent study published in The Lancet back in April, some findings point to the virus attacking endothelial cells, which protect the cardiovascular system through blood clotting and immune system response. These findings were consistent with the damage to those cells in several major organs, including the lungs, heart, liver, kidneys and intestines.