The SARS-CoV-2 pandemic is putting a strain on health, social and economic resources around the world. Social precautions - safety distances, no gatherings, #RestiamoaCasa - are the key to stemming the spread of COVID-19. #Let's Away!
The Covid-19 coronavirus it is highly transmissible and knows no barriers. Neither geographical nor social. The R0 value expresses the number of cases of disease that an infected person can cause. The maximum likelihood (Maximum Likelihood, ML) of transmission, in the emblematic case of the Diamond Princess cruise ship - was estimated at R0 = 2,28. (1)
Lo Imperial College in London has in turn estimated a variable R0 between 2 and 3, in the 11 European countries considered so far. Noting how the containment measures adopted in Italy with the decree 11.3.20 #RestiamoaCasa have made it possible to reduce the number of actual reproductions (Rt) down to approximately 1. Be that as it may, 'with a high level of uncertainty'. (2) We are all in the same boat.
COVID-2 is mainly transmitted:
- among the people, through exposure to respiratory droplets (respirator secretions with a diameter> 5-10 μm) from an infected person. The micro-droplets can reach the mouth, nose (or eyes) of nearby people and be inhaled (thus reaching the lungs),
- by contact di surfaces touched by infected people, (3)
- in most cases, asymptomatic or pre-symptomatic person, not swabbed or registered. (4)
Transmission by air coronavirus - within the droplets nuclei, particles <5μm in diameter, which can remain in the air longer and beyond the 'safety distance' - cannot in turn be excluded. Although the only experimental study published on the subject so far, on the British Journal of Medicine, (5) was considered insufficient by the WHO (World Health Organization) to infer the effectiveness of this transmission path.
It is therefore essential to maintain always a minimum safety distance between people, which WHO indicates in at least 1 meter. (6) A minimum prudential distance that has been taken up in the containment measures established in many countries. But perhaps not prudent enough.
The safe distance recommended by the CDC (Center for Disease Control and Prevention, US government agency) is in fact 6 feet, equal to about 183 cm. (7) Almost double that recommended by the World Health Organization. By applying the precautionary principle - a duty, at least in Europe, in the event of scientific uncertainty about a possible health risk (8) - greater prudence must prevail.
Individual responsibility, please note, it can have a potentially epidemic social impact if the rules are violated or careless. A single distraction can be enough to contract or transmit Covid-19, and reactivate the chain of contagion.
▶ It is recommended therefore of:
- always keep a minimum distance safety of at least 1,5-2 meters,
- do not go out, outside the suns cases of need, until the authorities have declared the end of the quarantine,
- insulate at home (where possible) subject to risk. About-65, immunocompromised and people with other morbidities, (9)
- self-isolate immediately at home, in case of first symptoms. Follow the recommendations aimed at preventing the contagion of cohabitants and contacting the referring doctor,
- always wear a mask, when you are in the vicinity of other people (albeit, with due respect for the minimum safety distance). Even a non-surgical mask, please note, can reduce the risk to infect others,
- wash your hands often and with care,
- sanitize surfaces and objects commonly used (handles, buttons, remote controls, electronic devices and mobile phones above all), frequently, with disinfectant solutions,
- sanitize the mask, before any re-use.
It is not easy to predict when an effective vaccine or antiviral drug is actually available to all who need it. Researchers are hard at work, but even when a vaccine passes tests, its large-scale production will take at least 12-18 months. (10) And it is utopian to imagine universal vaccination in a shorter time than the spread of the virus in the five continents. All the more so when we consider that Covid-19 has already reached 200 countries. (11)
The only strategy to stem the COVID-19 pandemic, in the absence of effective pharmaceutical interventions, the one based on:
- drastic reduction of contacts between vulnerable and contagious people,
- assessment timely cases.
Just so the spread of the infection could be slowed and the intensity of the epidemic reduced. To reduce cases of premature mortality, ease the (overload) burden of health systems, allow the development and dissemination of adequate vaccines and therapies in the medium term (12).
#Let's stay away!
Dario Dongo
(1) Zhang S, Diao M, Yu W, Pei L, Lin Z, Chen D. Estimation of the reproductive number of novel coronaviruses (COVID-19) and the probable outbreak size on the Diamond Princess cruise ship: A data-driven analysis. Int J Infect Dis. 2020; 93: 201–204. doi: 10.1016 / j.ijid.2020.02.033
(2) COVID-19 Response Team. Estimating the number of infections and the impact of non-pharmaceutical interventional on COVID-19 in 11 European countries. Report 13 (30.3.20). Imperial College
(3) Ong SW, Tan YK, Chia PY, Lee TH, Ng OT, Wong MS, et al. Air, surface environmental, and personal protective equipment contamination by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a symptomatic patient. Published online March 4, 2020. doi: 10.1001 / jama.2020.3227
(4) Ruiyun Li, Sen Pei, Bin Chen3, Yimeng Song, Tao Zhang, Wan Yang, Jeffrey Shaman. Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV2). Science Mar 2020: eabb3221. doi: 10.1126 / science.abb3221
(5) Van Doremalen N, Morris D, Bushmaker T et al. Aerosol and Surface Stability of SARS-CoV-2 as compared with SARS-CoV-1. New Engl J Med 2020 doi: 10.1056 / NEJMc2004973. Other pre-published scientific studies are awaiting peer-review. A first study conducted by Hunan Provincial Center for Diseases Control and Prevention (China) was instead withdrawn a few days after its publication, which took place on 6.3.20 (v. https://www.egalite.org/coronavirus-persistenza-nellaria-e-distanze-lo-studio-cinese/)
(6) WHO. Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations. Scientific briefs. 29.3.20, https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations
(7) CDC (Center for Disease Control and Prevention). Coronavirus Disease 2019 (COVID-19). Protect yourself, know how it spreads, https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html
(8) The precautionary principle it forms the basis of European environmental policy (TFEU, Article 191.1) and should therefore always be applied. At least in Europe and possibly even globally, when a Constitution for the Earth (v. https://www.egalite.org/una-costituzione-per-la-terra/) will finally be established and shared. In the health sector, as in this case, but more generally on all anthropogenic activities. Including the management of chemical and organic substances, genetic engineering, agro-industry (v. https://www.greatitalianfoodtrade.it/sicurezza/pollo-al-cloro-carni-agli-ormoni-e-nuovi-ogm-dagli-usa-ttip-no-grazie)
(9) Zoltan Neufeld, Hamid Khataee. Targeted adaptive isolation strategy for Covid-19 pandemic. MedRxiv (pre-published study, pending peer-review). doi: https://doi.org/10.1101/2020.03.23.20041897
(10) Roy M Anderson, Hans Heesterbeek, Don Klinkenberg, T Déirdre Hollingsworth. (2020). How will country-based mitigation measures influence the course of the COVID-19 epidemic? Lancet Infect Dis https://doi.org/10.1016/S0140-6736(20)30567-5
(11) Worldmeter (2020). Covid-19Coronavirus outbreak, www.worldmeters.info/coronavirus
(12) Stephen Kissler, Christine Tedijanto, Marc Lipsitch, Yonatan H. Grad, Social distancing strategies for curbing the COVID-19 epidemic. MedRxiv (pre-published study, pending peer-review). Mar 2020, https://doi.org/10.1101/2020.03.22.20041079.
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.