José Luis Jiménez: “Contagion is twenty times easier indoors than outdoors”

One of the biggest mistakes made in this pandemic was to believe that the new coronavirus was only transmitted by droplets that we expelled by coughing or sneezing and that we called “ballistics”. This led to the misconception that it was enough to be at least a meter and a half away to reduce the risk. Today, we know that, on the contrary, the microorganism can remain floating in the air in fine aerosols which are propagated simply by breathing them.

José Luis Jiménez, a doctor of engineering from MIT and professor of environmental science at the University of Colorado, was one of those who fought an uphill battle for several months to get this notion accepted by the medical community. With colleagues from an international group, he has just published in The Lancet an article which gathers the reasons which support this assertion. “What we are showing is not only that it can be transmitted through the air, but that it is the dominant way in which infections occur, that transmission through surfaces is difficult and that these drops that l “WHO has proposed only happen if someone coughs or sneezes. Your face – emphasizes -. We need to focus the effort on the priority form of transmission.”

– What is the evidence that leaves no doubt that the virus is transmitted by aerosols?

– There are so many that it is difficult to quote them succinctly. First, thousands of examples of “superpropagation” have been studied. [como el del coro de Skagit, que se juntó sin saber que uno de ellos estaba enfermo y en el que luego de dos horas cantando, 52 de los 60 integrantes se había infectado]. They are all the same: people infected by sharing the air in a room. These cases cannot be explained by “ballistic” droplets or by contact with contaminated surfaces. There are cases of long-distance transmission, such as from a church in Australia, where people 15 meters behind an infected person have been infected, where it has been possible to prove by recorded videos that they do not. had no contact and that the genome of the virus is exactly the same. Then, the fact that half of the infections come from people who still have no symptoms. These people do not cough or sneeze, this implies that it must be done in the air. Then there’s the fact that contagion is twenty times easier indoors than outdoors, and indoor ventilation lessens it. This is only explained if you are going to smoke. If it is a “projectile”, the risk would be the same inside as outside. Health workers wearing masks to protect them from the drops were also infected. Viruses were found in the air which were then introduced into the cells and managed to infect them. It was discovered in construction tubes that it can only reach if it is in the air. Animal models such as ferrets and hamsters have been infected from the air. There is no study that demonstrates or offers no strong argument that it does not go through the air. And the last thing, and almost the most important, is that there is no evidence that it goes through surfaces or through those heavy drops.

– If there is so much evidence of contagion from aerosols, why is it so difficult for this idea to be accepted?

-For two reasons. Most importantly, there has been a historical error in the science and epidemiology of infectious disease. In 1910, a leading researcher in the United States proposed that if anyone was infected nearby, it was from these “ballistic” drops. In fact, he misinterpreted data recorded in Germany. But it was a great success and this vision became dogma that made the transmission of disease by air impossible throughout the twentieth century. With much effort, this fact has been demonstrated for a few: measles, tuberculosis and chickenpox. But for others, like the flu or SARS, there was a lot of resistance. So when this virus appears, they say the same thing: that it is a disease which is transmitted by “projectile” drops without any proof. It was a tradition, a dogma.

The second reason is of a practical nature: there has always been a great fear of saying that there is something in the air because it seems to the authorities that it is then like a ghost and people do not. do not know how to defend themselves. But it is precisely the reverse. We understand if we explain that it is something that passes through the air like tobacco smoke. When you breathe in a lot of tobacco smoke, what is another aerosol? When you are speaking right in front of another person or when sharing the air in a room. If you are outside, no. Not only is it easy to understand, but it is also not very difficult to defend yourself, nor very expensive. But instead, we disinfect the surfaces, which is unnecessary.

– Now, is this something definitively accepted?

– Most scientists agree with us, but the referents of epidemiology and infectious diseases, who have the upper hand at the WHO and in the ministries of health, are dogmatic. For 100 years, they’ve thought that this thing about flying through the air is nearly impossible. You are not studying something that is almost impossible, why are you going to study it? The WHO committee, which decides how diseases are transmitted, has six experts on how to wash hands and no expert on airborne transmission. So when this disease happened, what did they say? That you have to wash your hands, that the aerial thing was almost impossible. And they make mistakes as soon as they open their mouths and write embarrassing articles. There are several articles by these WHO committee experts in which nothing is correct. Everything is false. It is shameful.

–How long does the virus stay in the air based on your studies?

“About an hour or two.” During this time, either it comes out due to air infiltration, or it loses its infectious power. What is dangerous is that there are a lot of people in a room at the same time, it is the number of cases that arise: when they breathe the same air for a long time, or when they speak very close from someone. If you get to a place where someone has been infected two hours previously, it is very unlikely that you will be infected.

“Does a chin strap work?” Is it enough, as we said at the beginning, that even if you put a scarf around your mouth, you are protected?

–Any chin strap helps. But a scarf protects you 10% and it is not that difficult to reach 50, 60 or 70%. This is the simplest thing. At first, when they told us it was dripping, the jugular was a parapet, like a barrier that covered them. But if it goes through aerosols, like cigarette smoke, it gets into all the gaps. There are colleagues in Germany who have shown that if you have a chin strap with a very small hole, 1% of the area, half of the air goes through. It goes where it costs the least and exits or enters through the hole rather than through the filter. We must therefore put the batteries and wear good quality chin straps, which do not leave us any holes. A good chin strap leaves a mark on your face; it is the signal that seals the air inlet and outlet.

– What do we know about the air inside public transport?

– There are subways that we are studying that have good ventilation. They change the air very quickly, so maybe you don’t need to keep the windows open. But on the buses you see a lot more variety, depending on the model, the manufacturer, the age. Many are not well ventilated and the only way to be sure is to open the doors wide or to have fewer people, or both. You should also be concerned that people are wearing tight-fitting masks and not talking. When you speak 10 times more viruses are released into the air and when you sing or speak loudly 50 times more. Not speaking or turning down the volume reduces the risk for everyone.

–How to act in closed places where many people gather, such as offices?

–The easiest and cheapest thing is to do activities outside in good weather and whatever activities you can. It’s free. The next thing to do is to open the windows, although during the winter there are heating costs. What we must avoid at all costs is to use chemistry. Note that I am a chemist, but I say you have to avoid chemistry. Systems with ions, with plasmas, with photocatalysis, with hydroxyl, or putting disinfectants in the air, like ozone, hydrogen peroxide, hypochlorous acid or chlorine dioxide, all of this is outrageous. And in my opinion, it should be banned. It’s dangerous.

– What advice would you give to families? Is it wise to meet with the windows open?

– What I tell my family is that it is better if they meet outside, with a little distance and a good mask, you are very safe. If you get together indoors, you always take a little more risk. So yes, open multiple windows continuously when people are present. It is sometimes thought that the ventilation opens before people arrive. No, during the time that people are, constantly, so that if viruses get into the air, they disappear. And I would also advise meeting a chin strap if possible. Especially if there are people at risk or older adults.