Although the research is yet to be published or peer reviewed, the preliminary findings could have major implications in developing strategies for halting the spread of the COVID-19 pandemic, according to a Monday letter from the study’s authors.
“Further studies are needed to assess the viral titer [concentrations] present in speech-induced droplets in asymptomatic COVID-19 positive persons, but our results suggest that speaking can indeed be a major mode of SARS-CoV-2 transmission,” wrote the researchers.
The study used laser imaging to detect thousands of droplets ejected when a person said the words “stay healthy.” Researchers said that although droplets produced during speech are tiny, they can transmit a broad range of respiratory diseases. Speech is also said to produce more droplets than coughing, which may be a more obvious mode of transmission.
“Droplets emitted while speaking are much smaller than those emitted when coughing or sneezing,” the researchers wrote. “Nonetheless they are sufficiently large to carry a variety of respiratory pathogens, including the measles virus, influenza virus, and Mycobacterium tuberculosis. Moreover, multiple studies have shown that speaking actually produces significantly more droplets than coughing.”
The research also found that wearing a cloth mask while talking reduced droplets produced to background levels. If the findings of the study are confirmed, researchers suggested wearing a face covering could help reduce the spread of COVID-19, especially when combined with other widely recommended public health measures.
“If speaking and oral fluid viral load proves to be a major mechanism of SARS-CoV-2 transmission, wearing any kind of cloth mouth cover in public by every person, as well as strict adherence to social distancing and handwashing, could significantly decrease the transmission rate and thereby contain the pandemic until a vaccine becomes available,” they wrote.
The advice mirrors updated guidelines by the Centers for Disease Control and Prevention (CDC), which began recommending the public wear cloth face coverings on Friday. The World Health Organization reviewed guidelines but still had not recommended masks or face coverings for healthy individuals as of Tuesday.
The CDC’s decision was based partly on recent research that has indicated a significant portion, perhaps the majority, of COVID-19 cases are acquired from people without any symptoms of the illness.
Other research has suggested that the virus can remain suspended in the air for hours, making it possible in theory for a person to acquire the virus by breathing in an area that an infected person passed through, although this is not believed to be a major mode of transmission.
Newsweek reached out to NIH for comment but did not receive a response in time for publication.
