The WHO’s latest report on its definition of airborne infectious disease is titled, “Global technical consultation report on proposed terminology for pathogens that transmit through the air.”

Three years after the outbreak of the COVID pandemic, 500 scientists, including physicists, public health professionals and engineers of the World Health Organisation (WHO) had concluded that COVID was airborne. That the pathogens were carried forward through air. In the beginning of 2020, when the virus spread across national borders from Wuhan in China, the WHO stuck to the argument that it was an infectious disease that spread through touch.

That is why, the WHO had issued advisories and warnings about washing hands frequently, not touching doorknobs, or the buttons in an elevator. People were asked to change clothes when they returned home, and doctors and nurses were forced to stay in hospitals and not go home. Quarantine was imposed on whole cities, shutting down everything.

The interpretation at that time swung between Covid virus spread through droplets, though there were quite a few doctors who pointed out that the virus was carried through aerosols. Some of the doctors have pointed out that the wrong reason given for the spread of the virus had led to many deaths. The question now being raised is why has WHO announced its decision of COVID being an airborne infection. This is to make it clear that just as there are water-borne infectious diseases like cholera, there are airborne infectious diseases like COVID. This is expected to help create clarity in dealing with infectious diseases in the future.

Soumya Swaminathan, who was the chief scientist at WHO in 2020, had argued that the view that COVID was airborne should have been argued more forcibly. Swaminathan’s successor, Jeremy Farrar, who was then head of the Wellcome Trust charity and advised the British government, argues that the WHO had acted in “good faith” and that the experts did not have enough evidence to the contrary. Now that it has been identified that the pathogens of a virus are airborne, then the strategy to combat it will evolve appropriate response. An airborne infection would require more ventilation in hospitals, homes, schools.

More than 200 aerosol scientists had complained in July 2020 that WHO had failed to provide proper guidance in the case of coronavirus. Jose Jimenez, a University of Colorado chemist, who had signed the letter of protest, said then: “WHO’s slow motion on the issue is unfortunately slowing the control of the pandemic.”

Dr. Walter Zingg, an infectious disease expert at the University of Zurich, and who was an adviser to the WHO expert group said that the earlier guidelines of keeping distance from a person sneezing or coughing were simple though it was not accurate. “It was simplistic and not true in a way, but it served a purpose. Now we have to bring other variables to the table.”

It is understandable that it is difficult to define precisely the nature of an infection because there is no rigorous empirical evidence to back it up. So, it will remain in a state of trial and error, part guesswork and part evidence. The WHO’s latest report on its definition of airborne infectious disease is titled, “Global technical consultation report on proposed terminology for pathogens that transmit through the air.”

It became evident that the terms of airborne transmission or transmission through the air were used in the different disciplines and they carried different meanings. An attempt was made to gather the different definitions and find a common denominator. It was also recognised that there was need to gather more evidence for each of the uses of the terms. It is the definitions that would guide the responses, especially with regard to airborne transmission. This could mean increase in ventilation in buildings.