In an attempt to stop the contagion of the coronavirus, among other measures, restrictions on mobility have been implemented, both perimeter (municipalities and autonomies) and in schedules , with night curfews that discourage leisure and celebrations. It will be enough? We must avoid going back to home confinement last spring.
The Washington Choir
A clear example of the risk posed by the interiors occurred in a choir rehearsal during the month of March in the state of Washington in the United States.
A total of 61 choir members were gathered and singing in a closed room for two and a half hours. One of them had symptoms (cough and fever) and days later it was confirmed as a positive case of covid-19. A total of 52 (87%) were infected, three required hospitalization, and two died. Only nine showgirls were spared.
The religious house of Madrid
At the other extreme, underlining the effectiveness of social distancing measures and masks, is the experience lived in a large house of nuns located on the outskirts of Madrid.
During the month of March, the 25 cohabiting women made an effort to ventilate the house, avoid crowds in living rooms and in the dining room, as well as carry out activities in the large garden of the farm. Although 21 (84%) were infected, none required hospitalization or deaths, despite the fact that half were over 65 and some were over 80.
The experience of the recent opening of schools goes along the same lines. The educational centers that have implemented social distancing measures and the use of masks have barely had infections at school. On the contrary, much evidence suggests that the positive cases diagnosed in schools have occurred in students who had attended after-school meetings without sufficient precautionary measures.
Five measures to reduce the risk of contagion in closed spaces
Now that the cold has arrived and we are inevitably going to carry out activities in closed spaces, what measures can we take to reduce infections?
1. Use large spaces better than small rooms. This is the case of warehouses, large classrooms, etc. The larger the room, the lower the concentration of viral particles found in the air we breathe.
2. Ventilate rooms frequently. Air circulation dilutes the viral density and the risk of exposure to high inoculums.
3. Wear a mask at all times and only remove it temporarily if you have to eat or drink. It must be worn properly, covering the nose and mouth, which is where the receptors used by the coronavirus to infect the human body are.
4. Keep distances between people. Avoiding being too close makes it difficult for the aerosols emitted when speaking to convey respiratory drops with virions to the face of the interlocutor.
5. Reduce the time of group meetings. The shorter the duration of a group activity in an enclosed space, the lower the risk of inhaling circulating virions in the room air.
Use rapid antigen tests before the meeting
In addition to the aforementioned measures that seek to reduce exposure to the coronavirus, a new tool has appeared in recent weeks to reduce the transmission of the coronavirus. These are rapid antigen tests. Its usefulness is extraordinary if used properly. It is about identifying all those who, with or without symptoms, could be contagious at that time. Exclusion from an event in an enclosed space would dramatically reduce the risk of transmitting the infection to attendees.
Rapid antigen tests have been approved by regulatory agencies, so they have sufficient sensitivity and specificity. They serve to replace PCR as screening tests. They have several advantages over PCR:
1. They are cheaper. While PCRs cost more than € 100, rapid antigen tests cost less than € 5.
2. They do not require sophisticated laboratories for its realization . They are made anywhere. At the pharmacy, at the doctor’s office, at home, etc.
3. The result is available in less than 15 minutes , whereas PCR requires several hours and, very often, the result is not given until the following day or days.
4. They are easy to interpret and do not require specialized personnel, such as those who must report the PCR. The result of the covid-19 antigen is recognized with a band on a plastic strip, like a pregnancy test.
5. They better reflect the contagious phase , because the antigen recognizes active viral replication, while PCR identifies fragments of the coronavirus genome, even when it is no longer contagious. In fact, CRP can remain positive for up to five weeks after the infection resolves. By then there is no risk of contagion, a period that does not last more than 7-10 days.
To maximize the effectiveness of rapid antigen tests, several improvements are necessary:
They should be able to be done with saliva rather than requiring a specimen collected from the oropharynx. Although the latter is less bothersome than taking nasal swab from PCR, taking saliva is much easier.
They should be available in packages of 25 to 100 tests for sale to the general public in pharmacies, such as pregnancy tests. Of course, it will be recommended to consult the doctor in case of positivity.
With all of the above, the prospect of Christmas holidays with the family is looming as possible, without the risk of coronavirus. But it is necessary the responsibility of all to live the commented measures.
Vicente Soriano, Faculty of Health Sciences & Medical Center, UNIR – International University of La Rioja
This article was originally published on The Conversation. Read the original.
