By Sharon Atieno

As Africa surpasses the 500,000 mark of COVID-19 infections, the World Health Organization (WHO) confirmed that there is “emerging evidence” of airborne transmission of the disease.

This is after a letter signed by 239 scientists was published urging the global body to be more forthcoming about the possibility that people can catch the virus from droplets floating in the air.

This reiterates sentiments shared earlier by one of the world’s leading experts in microbiology and infectious disease, Prof Kazuhiro Tateda, President of Japanese Association for Infectious Diseases.

“It seems transmissions are happening during conversations and even when people are standing a certain distance apart. These cases can’t be explained by ordinary droplet infection. We think infection comes from “micrometer particles”. This transmission mechanism can be called “micro-droplet infection which occurs when people are in close contact to or when just talking,” Prof. Tateda and his team claimed.

“Micro-droplets carry many viruses. We produce them when we talk loudly or breathe heavily. People around us inhale them, and that’s how the virus spreads. We’re beginning to see this risk now,” Prof. Tateda said.

According to Dr. Benedetta Alleganzi, WHO Technical Lead for Infection Prevention and Control, the agency has discussed and collaborated with many of the scientists who signed the letter.

“We acknowledge that there is emerging evidence in this field, as in all other fields regarding the Covid-19 virus and pandemic and therefore we believe that we have to be open to this evidence and understand its implications regarding the modes of transmission and also regarding the precautions that need to be taken,” Alleganzi said.

Infectious disease epidemiologist Maria Van Kerkove, with WHO’s Health Emergencies Program said that they have been talking about the possibility of airborne transmission and aerosol transmission as one of the modes of transmission of Covid-19, as well as droplet. WHO has looked at fomites, fecal oral, mother to child and animal to human transmissions.

Van Kerkove, said WHO is working on a scientific brief summarizing the current knowledge around transmission of the deadly virus, which should be available in the coming weeks.

“So, these are fields of research that are really growing and for which there is some evidence emerging but is not definitive,” she said.

“And therefore, the possibility of airborne transmission in public settings, especially in very specific conditions crowded, closed, poorly ventilated settings that have been described cannot be ruled out. However, the evidence needs to be gathered and interpreted.”