Since the arrival of the coronavirus, uncertainty has loomed over many facets of the new virus, including how long it can survive on surfaces and other questions about transmission.
Even the extent of immunity it provides its survivors with and the efficiency of various medications used in treating it are still a matter of debate.
One of the aspects of coronavirus that has been shrouded in mystery was whether the virus can stay aloft for hours in stagnant air, infecting people as they inhale.
The World Health Organization said in March that it could not, but is now backing evidence that states otherwise.
"It is unclear how often the virus is spread through these tiny droplets, or aerosols, compared with larger droplets that are expelled when a sick person coughs or sneezes, or transmitted through contact with contaminated surfaces," said Dr Amr Saleh, a chest disease consultant.
Oxford University Press published a study by the Infectious Diseases Society of America on 6 July providing evidence that aerosols that are released even when a person without symptoms exhales, talks or sings pose a risk that is highest in crowded indoor spaces with poor ventilation, and may lead to super-spreading.
"For a virus to be airborne means that it can be carried through the air in a viable form. HIV for example is too delicate to survive outside the body, and so is not airborne. Measles is airborne and can survive in the air for up to two hours. But for the coronavirus, it is more complicated,” said Saleh.
"The mentioned paper submitted to the WHO is one of the many pieces of evidence that conclude that aerosols of infected people with coronavirus can hang in air for hours, so people should consider minimising time indoors with people outside their families, and schools, nursing homes and businesses should consider adding powerful new air filters and ultraviolet lights that can kill airborne viruses," Saleh says.
Avoiding a rush to judgement
Dr. Adel Khattab, professor of pulmonary medicine at Ain Shams University and a member of the Supreme Committee for Viruses, is sceptical to some extent.
"From the onset of the pandemic, various health sources, among which was the WHO, identified large particles of droplets as the main source of infection. These large particles are transmitted through respiration, coughing and sneezing, and can reach people if they are not further than 5 or 6 feet away from the infected source,” he said.
"When a symptomatic person coughs or sneezes, theses relatively heavy droplets fall quickly to the nearest surface, hence the recommendations of social distancing.”
"What the WHO is backing now is negating what they stated before, and actually negating logic,” he said.
"We have to understand the difference between droplets and aerosols, which is nothing actually except a matter of size.”
“Some experts now are claiming that infected people release aerosols when they breathe or talk and because aerosols are smaller and lighter, they can linger for hours especially in the absence of fresh air, thus infecting people for hours, even if they are not close to them," Khattab says.
Khattab stresses that these fears are unlikely, and says that not all claims can be regarded as facts when it comes to the current situation, even if the source is a high authority like the WHO.
"We have seen entities discarding drugs that were saving lives in many countries, and then changing their status to approval and vice versa. We have seen the WHO 'discontinuing' antiviral drugs that were saving lives and the same for hydroxychloroquine on 17 June, although the latter was an established medicinal solution for many COVID cases worldwide,” he said.
"The same for the idea of 'airborne COVID’; it was a claim at the beginning of the crisis that the WHO pointed out, then disregarded, and now it is backing it again. In such a situation, there should be no rush to adopt a fixed opinion, especially as, if such a claim is accurate, the situation in many countries would have been more disastrous. We have to take into consideration that a lot of 'politics' and commercial benefits play a backstage role in what is publicly being said," he says.
Khattab says that, nevertheless, precautionary and preventive measures should not be undermined.
"People who work in direct or close contact with symptomatic persons should wear the N95 mask to prevent the tiniest particles from getting through, as well as a face shield. Otherwise the normal face mask suffices, as well as abiding by the normal rules of social distancing, washing hands frequently, and opting for open-air areas for gatherings,” he said.
"As doctors and medical entities we have been monitoring the situation and studying the latest claims, along with experts at the Supreme Committee for Viruses, and we have been seeing a decrease in the numbers as well as the intensity of the disease, so there is no need to panic now, as long as the basic regulations mentioned above are abided by.”
"Provided that we adhere to precautionary and preventive measures, things are certainly getting better. For now? Better ventilation, social distancing, washing hands frequently and keep wearing those masks," he concluded.