Some lessons on respiratory disease transmission have been offered by the Covid pandemic. Those insights can be used to create infection control policies that are even smarted, according to a new review.
Some of the tactics to control infections are outdated at hospitals
Outdated Infection Control Practices Are Put Under Scrutiny By Pandemic. Greater use of N95 masks and other such changes might be in order. Dr. Micheal Klompas, the lead review author said that respiratory virus transmission has been falsely simplified and current measures to control infections are based on this. Relatively heavy particles that people expel when they exhale are known as ‘droplets’. Most respiratory viruses like flu and the common cold are mainly transmitted this way, according to traditional teaching. These are adequately blocked by a surgical mask and they fall to the ground within feet of the person who has been infected. Some other viruses, like measles and tuberculosis, are usually airborne. This means that, via tiny aerosol particles, they can be transmitted among people. These particles remain suspended in the air for a longer time, and in a poorly ventilated space, they can accumulate.
Some of these minute particles are blocked by surgical masks, but not all of them. Policies at hospitals have been guided by this droplet/aerosol premise. N95 masks are usually reserved for procedures that generate aerosols. Procedures like inserting a ventilator tube generate aerosols. Klompas said that the droplet/aerosol divide is a dubious one according to recent research. Klompas is an infectious disease expert. He said that most of what we exhale is aerosol and added that almost all respiratory viruses, to some degree, have the ability to transmit themselves through these particles. The distinction between droplets and airborne came from observations that regarded proximity. The flu and most other respiratory viruses are usually passed through people who have been in close contact. People can be infected even at larger distances by pathogens like the measles virus. An international sport that was held in a domed stadium was the cause of a measles outbreak in the 1990s in the United States.
In order to explain the differences in viral transmission, these differences in droplet and airborne categories arose. Klompas, however, said that ventilation and other factors are more key. In a well-ventilated area, even airborne pathogens become diluted very rapidly. This lowers the risk of infection. It was found in a study of train passengers that occurred during the pandemic that people who were sitting next to a person who did not have any symptoms of Covid were 10 times as likely as passengers who were seated 3 seats away to get infected. The protection given by distance is lowered by poor ventilation.
The amount of time during which the exposure occurs is also important. He explained that even in areas that were well ventilated, the duration is important. It was found in the same study that passengers who were on a long journey were more likely to get infected. Transmission is influenced by differences among respiratory viruses themselves. The differences among people that are infected is also influential. People tend to be more contagious if they have a high viral load. Dr. David Henderson co-wrote an editorial that was published along with the review. He said that it was a great paper, and it highlighted the point that between droplet and aerosol, there was no strict dichotomy. According to Henderson, the practical implications are more complicated. He said that along with eye protection, surgical masks have worked very well in preventing the breakout of Covid among healthcare workers. Henderson noted that other respiratory infections have disappeared in hospitals.
