A new study reveals that people who are the least symptomatic of COVID-19 may have the highest viral load of the virus and can therefore be the most dangerous transmitters of disease.

The American Journal of Pathology reports that investigators at New York University Langone Health found that the amount of SARS-CoV-2, called the viral load, measured in patients was much higher in those with the mildest symptoms and who did not require hospitalization.

According to Scienmag, that’s the opposite of the result researchers expected. They also discovered that if a patient had a history of cancer or cardiovascular disease, these factors also increased their viral load.

“It appears that the viral load peaks in the early stages of the disease,” said Paolo Cotzia, M.D., one of the lead investigators from NYU Langone Health. “Whether the viral load in these patients stays the same or changes in later stages remains to be investigated.”

The researchers also found that patients who did require hospitalization had lower viral loads compared to those who were discharged even after age, sex and other adjustments were made by scientists.

The new evidence contradicts a previous Chinese study published in The Lancet that said patients with severe COVID-19 tend to have high viral loads and mild cases had an early viral clearance.

The NYU Langone Health researchers said that their study punctuates the need for everyone, even people who are asymptomatic, to wear masks and observe social distancing to avoid transmission of the coronavirus.