[Date of latest publication cited: September 20, 2021]
Since the pandemic started, many organizations published information on these topics in three types of formats:
- Medical and public health science journals published hundreds of thousands of new research reports on COVID-19. Thousands were published on preprint servers, over 100 times the rates of previous epidemics (Brierley). It is impossible to keep up with reading them, so scientists needed to create new methods of vetting, selecting, organizing, and synthesizing them (Bauchner et al.; Brainard; Callaway; Else; Gopalakrishna; Ioannidis et al.; Kwon D; The Lancet Global Health “Publishing”; Packer). Scientific journals accepted and published COVID-19 papers faster than other papers before, and reduced the numbers of non-COVID-19 papers (Aviv-Reuven et al.).
- A variety of news media published summaries of the research articles in plain language which each linked to a one or a few research articles, often within hours after the scientific journal article was published. But these news stories are scattered across many print, TV, and online locations. Then other stories displace them. Often a new discovery partially contradicts previous ones. People wondered, which recommendation should I and our group members act on? How can I find that explanation or recommendation I saw days ago?
- Public health organizations, health experts, and some online magazines posted summaries of what people should do in different situations. But they had few links to the research articles, if a reader wanted to know the science behind the recommendation. Some had difficulties keeping up with the new research studies published each day, so in many of those health web pages the latest information was published weeks before (Aubrey et al.; Bromage; California; Centers for Disease Control and Prevention “Considerations…”; “Coronavirus”; “COVID-19 Employer…”; “Funeral…”; “When…”; “Returning…”; Ernst, Beamer; Lopez, Northrop; Safety.com; San Diego County; Sneider; World Health Organization “Coronavirus”).
So this web page meets the needs of people who want a synopsis of the latest discoveries on COVID-19 transmission and prevention, in one location, in plain English, with links and references to the many research articles supporting each statement. Most people’s information needs are satisfied by the news reports and public health recommendations. But many health professionals, researchers, interested people, and leaders of organizations and groups would want this web page’s “one stop shopping” summary with links to each scientific article explaining the reasons for the recommendations.
Most articles referred to here are peer-reviewed journal publications, or preprint postings from medRxiv and bioRxiv, or popular science articles, or companies’ web sites with reliable information. I searched PubMed for peer-reviewed or good quality articles, preprints, and research reports specifically on transmission routes of coronavirus disease COVID-19, using the search terms “coronavirus”, “COVID-19”, “SARS-CoV-2”, “2019-nCoV”, “transmission”, “saliva”, “mucous”, “blood”, “feces”, “fecal”, “fomite”, “surface”, “droplet”, “aerosol”, “asymptomatic”, “pregnancy”, “birth”, “childbirth”, “dog”, “cat”, “sexual transmission”, “vagina”, “testes”, “semen”, and “food”. I included original research studies of the community transmission routes of COVID-19 infected people. I excluded publications on: nosocomial infections in health care facilities; pathology; medical treatment; other coronaviruses; epidemiology and demographic statistics and disparities; mathematical models and predictions; and zoonotic origins from animals. Articles published in English, and some translated from Chinese, were included.
Researchers are publishing new articles daily, so I will continue updating and revising this web page daily. I selected articles with tangible, practical answers to four questions:
Which bodily fluids transmitted SARS-CoV-2 from an infected person to another person?
Which tissues and organs received SARS-CoV-2 and started developing infection?
Which non-pharmaceutical methods could people use to prevent these transmissions?
What other factors affected these processes, including air, locations, and immunity?
This approach differs from a review of the literature which counts the numbers of articles writing about each topic, and summarizes consensus on each.