MVS- Pharma on Aerosols
In conjunction with our ongoing research, MVS-Pharma recognizes the significance of aerosols. Here, we are delving deeper into the issue.The importance of aerosols in the transmission of SARS-CoV-2 remains widely underestimated. Exactly what role do aerosols play in the transmission of SARS-CoV-2?
There are three transmission routes for SARS-CoV-2:
- Contact surfaces: Infection occurs via contaminated surfaces, such as touching door handles or when shaking hands
- Droplets: When an infected person coughs or sneezes, droplets larger than 100 μm are emitted. These fall to the ground after one to two meters - they shouldn't hit someone beforehand
- Aerosols: The droplets are smaller than 100 μm, and they are released as you breathe and when you speak. They can remain in the air for several hours and cover longer distances
In our opinion, aerosol contamination is being given far too little attention by health authorities and the general public. The WHO, for example, classifies aerosol transmission as possible, yet with much lesser chance compared to droplet transmission, despite sound scientific evidence. According to the health authority, infection via contact surfaces and droplets are the main routes of transmission.
At MVS Pharma, on the other hand, we view aerosols as an important, if not the most important, transmission route. Our stance on this has remained consistent throughout the course of the pandemic. We have justified this, among other things, with the fact thatasymptomatic patients also infect other people. These patients do not cough or sneeze (or, if they do, only a little) and thus do not release larger droplets, whereas aerosols do.
MVS-Pharma has long championed the need to recognize the irrefutable capabilities of aerosol transmission, and we have implored our peers and the world at large to acknowledge this too.
Our beliefs were confirmed by a study published in August 2020 that found that a single person in the early stages of Covid-19 could emit millions of SARS-CoV-2 particles per hour through breathing alone. (Ma J, 2020) We have no doubt that further research will prove the vital need to recognize the killer in our midst.
At this point, we would also like to clear up a major misunderstanding. For a long time, it was said that aerosol droplets loaded with viruses cannot be larger than 5 μm because they float in the air for an extended period. According to our research results and those of many other institutes, it has been shown that even larger droplets can remain in the air longer; at room temperature for about one to two hours.
The dogma of droplet infection:
One point that critics of the aerosol theory persist in making is that SARS-CoV-2 would have to be much more contagious if aerosols were the main transmission route - as is the case with measles. But scientists say that's just a myth. There is no reason why nature only produces highly contagious viruses that spread via aerosols. Other viruses (such as influenza) are sometimes spread via aerosols and are not as infectious.
There are most likely historical reasons for neglecting aerosol transmission theory. Influential infectiologists contributed a great deal to the understanding of infectious diseases at the beginning of the 20th century by correctly observing and recognizing connections. In doing so, the contagion via droplets became an incontrovertible fact that does not require further proof.
Over time, the droplet infection mode became thedogma of the transmission of respiratory diseases. This fact remains unquestioned by many experts today. Due to this, health authorities such as the WHO and the Centers for Disease Control (CDC) fail to deviate from looking for the main transmission path of SARS-CoV-2 in droplets. However, there is now a great deal to be said for the aerosol transmission path, and this is increasing by the day.
What role do temperature and humidity play in transmission?
The following applies to indoor transmission: SARS-CoV-2 prefers a cold and dry environment. In dry air, the lipid-enveloped viruses seem to survive longer, and virus-laden droplets can remain in dry air for longer too. When the humidity is high, the droplets become larger and more likely to fall to the ground. In addition, dry air makes people more susceptible to infections. Please note the fact that temperature and humidity only play a role when transmitting over a longer distance. In the case of direct contact, this is negligible.Should masks also be worn indoors?
If the clearances cannot be maintained indoors, masks should be worn. Doing so canirrefutably prevent the spread of the virus because discharged particles are retained. In addition, masks could also protect the wearer themselves to a certain extent, according to many reports.
At MVS-Pharma,we believe it is vital to dispel the prejudices surrounding mask-wearing. It is sometimes said that wearing masks is ineffective and does not help whatsoever because the viruses could get through the pores - unless you use a special FFP2 mask. If one assumes that viruses always float through the air, then this assumption could be valid. However, since the viruses also travel around in droplets, masks can interrupt the flow of particles to some degree. Of course, that also depends on the material used and the adequacy of the fit of the mask itself.
Aerosols and Corona:
The 10-Point Proof
There have been many Corona outbreaks on cruise ships and after large gatherings and celebrations –and usually, a single "super-spreader" is at fault. They're deemed as being responsible for infecting numerous other people. Super-spreaders are infected people who have a particularly large number of tiny infectious droplets that disperse outward while breathing and speaking. There are estimates that 10 percent of those infected could be responsible for 80 percent of the infections.
Detailed studies of such super-spreading events give clear indications that the virus is mainly transmitted via aerosols. The super-spreader is most likely to infect people in its immediate vicinity and also people at a greater distance. These instances cannot be explained with contaminated surfaces or classic droplet infection theory, but rather through the dilution of the exhaled aerosols with increasing distance from an infected person (refer further to point 10).
The virus appears to be capable of traveling long distances in aerosol clouds. There are reports from quarantine hotels in which people in neighboring rooms were infected despite never coming into direct contact with one another. The authors were able to rule out transmissions via surfaces by means of detective research and reconstructions, including camera evaluations.
In this exemplary case, the aerosol transmission clearly appears to be the only logical explanation. At the time when the infected person was tested in the hallway, the doors of both hotel rooms were open for around one minute. Analysis of air pressure in the rooms and hallway suggests that there must have been an exchange of air between the spaces. This air exchange between rooms and hallway seems to have been enough for the infectious aerosol cloud from one room to find its way to the next.
The asymptomatic or presymptomatic transmission of SARS-CoV-2 likely accounts for at least a third of all infections. Asymptomatic/presymptomatic people do not cough or sneeze (or only a little) and thus do not release larger droplets, whereas aerosols do. Measurements show that thousands of aerosol particles are formed when speaking, but only a few large droplets. These factors again speak in favor of a predominantly air-transmitted mode of transmission.
The transmission of SARS-CoV-2 indoors is much higher than outdoors, and frequent ventilation reduces transmission significantly. Both observations are highly indicative of the validity of aerosol transmission and serve to quash the preeminence of sole transmission via larger droplets that quickly fall to the ground or contaminated surfaces.
There is vast evidence of Nosocomial infections that developed in clinics and nursing homes worldwide,despite strict precautions being taken against the spread of droplets. However, not against aerosols, such as the study by Klompas et al. suggests.
We have succeeded in detecting infectious SARS-CoV-2 viruses in room air –and an attempt is currently being made to cultivate viruses from air samples. This is a decidedly demanding technique, which is why some studies have thus far been unable to prove it.
The infectious viruses in indoor air were also found in COVID-19 patients who were not subjected to aerosol-generating medical measures, such as intubation.
SARS-CoV-2 could be detected in air filters and ventilation shafts of clinics with COVID-19 patients. The virus can only reach these places via aerosol clouds. Whether the infections occur in restaurants, open-plan offices, ships, or airplanes - since the pandemic outbreak, infections have been reported at regular intervals whereby it is suspected that the virus was able to spread via the ventilation system.
Very recently, such a case was reported again: In an airplane that flew from New Delhi to Hong Kong on April 4, upon arrival, an initial 47 passengers tested positive for SARS-CoV-2. After a 12-day quarantine of the passengers, 22 new positive tests were added.
Studies such as those by Kutter et al. have shown that infected caged animals can infect other animals whose cages are only connected via an air duct. Here, too, transmission can only be explained by aerosols.
To date, there has been no study that provides solid or consistent evidence to refute the hypothesis of airborne SARS-CoV-2 transmission.
There are reports in which people did not become infected with SARS-CoV-2 even though they shared the air with infected people. But this situation could also be explained by the fact that infected people excrete different amounts of viruses (see point 1), and certain environmental conditions exist – in particular adequate ventilation.
As we discussed earlier, we are aware of the historical reasons for neglecting aerosol transmission theory and why it has long been assumed that such a transmission through close proximity requires exposure to large droplets or contact areas. With this erroneous assumption held firm, the aerosol transmission of tuberculosis and measles was denied for decades –yet it is now known that both pathogens are mainly transmitted via aerosols.
This also seems to be the case with SARS-CoV-2: The slight contagion between people in close proximity to one another has long been cited as evidence of the transmission of SARS-CoV-2 through large respiratory droplets. However, transmission in close proximity in most cases, and remote infection in a few cases when the air is shared, can be explained by the dilution of the exhaled aerosols with increasing distance from an infected person.