One hundred scientific and sanitary Spanish people, among which are Alfredo Corell, Professor of Immunology at the University of Valladolid, Director of the Institute for Health Research of the Hospital Universitario La Paz Eduardo López-Collazo, CSIC virologist Margarita del Val or Dr. César Carballo, assistant to the emergency service of the Hospital Universitario Ramón y Cajal, have sent a letter to the Government and the Communities urging to take urgent measures against transmission of the Covid by aerosols, since these have a “dominant role in the contagion indoors”.
The specialists ask the authorities to “rethink the prevention recommendations” to reduce the infected by coronavirus when the WHO has already given a warning signal about a possible rebound for Easter. In this sense, they point out that the scientific evidence provided throughout the pandemic excludes measures such as the need to clean surfaces, a measure that could be “saved” for “cto make the reduction of the risk of contagion by inhalation of the virus the highest priority ”.
“Despite the clarity of the scientific conclusions, the implementation of these measures is being extraordinarily slow, and many times it is carried out partially or incorrectly,” lament the experts. Therefore, they urge “coordinated and urgent action by all competent administrations to address as a priority the transmission of SARS-CoV-2 by inhalation of aerosols ”, around eight major elements:
1- Masks: It is urged to remove the mesh masks or ‘hand guards’, to carry out “massive information campaigns” on how to wear them correctly, and to demand their use indoors in workplaces, where indoor air is shared for many hours, although the safety distance of 2 m is maintained.
2- Open air: Given that the possibility of contagion is “20 times less” abroad, it is urged to “keep parks and gardens open”, a “beneficial measure for the population”; to take advantage of the “good weather” to hold meetings abroad; and to check the closed terraces, which can be counterproductive.
3- Ventilation with outside air: Experts ask that it be carried out continuously, using natural or mechanical ventilation or a combination of both, with a rate of at least 12.5 liters / second per person.
4- CO2 measurements: “It is the best, if not the only, low-cost technological solution available to verify at all times if the ventilation is sufficient or if it is necessary to increase it,” they write. Therefore, they ask its urgent and widespread implementation, with reliable meters (NDIR type).
5- Air cleaning: Both for the case of high-efficiency filtering (known as HEPA filters), “a proven solution for the elimination of respiratory aerosols”, as for technologies such as UV-C, photocatalysis, ionization, ozone, etc., it is necessary to “clearly define which are the recommendations for use”.
6- Focus on schools: “Until now, the centers have received ambiguous and even contradictory information. We consider it essential to implement in a generalized way optimized ventilation strategies with outside air, using CO meters.2 and continuous, crossed and distributed ventilation ”.
7- Gauges according to CO2: When it comes to reviving the economy, they write, “capacity limitations have little technical justification and should be replaced by criteria of effective sanitation of the indoor environment (eg, in terms of CO levels).2, in addition to other essential measures such as the use of masks) ”.
8- Disclosure: Experts call for a great coordinated campaign on networks, TV, radio and press to improve what is available today. “Currently, if a person wants to be informed, he or she faces partial, confusing, sometimes too verbose and not infrequently incorrect or contradictory information… The way to offer clear, concrete, correct and organized information should be articulated, possibly with different levels of detail, accessible to any person or organization, public or private ”.