First published on 4 March 2020 and updated on an ongoing basis; last updated on 25 March 2021 (changes detailed below); all the reviews in this Special Collection are free to access
This Special Collection is one of a series of collections on COVID-19. It is also available in Simplified Chinese, Czech, German, Farsi, French, Japanese, Malay, Polish, Portuguese, Russian, and Spanish.
This Special Collection has been created in response to the COVID-19 pandemic and is regularly updated. It aims to ensure immediate access to systematic reviews most directly relevant to the prevention of infection. It includes reviews that are relevant to the WHO interim guidance, as well as other potentially relevant reviews from three Cochrane Networks: Cochrane Public Health and Health Systems; Cochrane Musculoskeletal, Oral, Skin and Sensory; and Cochrane Acute and Emergency Care, and also draws on the knowledge of Cochrane groups in affected regions. Many reviews in this collection have associated Cochrane Clinical Answers (CCAs), with links provided.
The different natures of pathogens and their modes of transmission compared with what is currently known about COVID-19 may limit the applicability of the evidence summarized in these reviews. Please note that the reviews included in this Special Collection summarize evidence, and their inclusion does not mean that the interventions reviewed have been shown to be an effective prevention measure.
Updated 25 March 2021: updated introductory paragraphs for the updated reviews ‘Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection’ and ‘International travel‐related control measures to contain the COVID‐19 pandemic: a rapid review’
Identification and diagnosis
Some people with SARS‐CoV‐2 infection remain asymptomatic, whereas in others the infection can cause mild to moderate COVID‐19 disease and COVID‐19 pneumonia, leading some patients to require intensive care support and, in some cases, to death, especially in older adults. Symptoms such as fever or cough, and signs such as oxygen saturation or lung auscultation findings, are the first and most readily available diagnostic information. Such information could be used to either rule out COVID‐19 disease, or select patients for further diagnostic testing. This review assesses the diagnostic accuracy of signs and symptoms to determine if a person presenting in primary care or to hospital outpatient settings, such as the emergency department or dedicated COVID‐19 clinics, has COVID‐19 disease or COVID‐19 pneumonia. Associated Cochrane Clinical Answer: What is the accuracy of World Health Organization (WHO)‐specified and related COVID‐19 symptoms for diagnosis of COVID‐19?
The severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) virus and resulting COVID‐19 pandemic present important diagnostic challenges. Several diagnostic strategies are available to identify current infection, rule out infection, identify people in need of care escalation, or to test for past infection and immune response. Serology tests to detect the presence of antibodies to SARS‐CoV‐2 aim to identify previous SARS‐CoV‐2 infection, and may help to confirm the presence of current infection. This review assesses the diagnostic accuracy of antibody tests to determine if a person presenting in the community or in primary or secondary care has SARS‐CoV‐2 infection, or has previously had SARS‐CoV‐2 infection, and the accuracy of antibody tests for use in seroprevalence surveys. Associated Cochrane Clinical Answer: What is the accuracy of immunoglobulin G (IgG) and IgM antibody tests for detection of SARS‐CoV‐2 infection?
Accurate rapid diagnostic tests for SARS‐CoV‐2 infection could contribute to clinical and public health strategies to manage the COVID‐19 pandemic. Point‐of‐care antigen and molecular tests to detect current infection could increase access to testing and early confirmation of cases, and expediate clinical and public health management decisions that may reduce transmission. This review assesses the diagnostic accuracy of point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection, and considers accuracy separately in symptomatic and asymptomatic population groups.
Interventions to reduce transmission in the community
In late 2019, the first cases of coronavirus disease 2019 (COVID‐19) were reported in Wuhan, China, followed by a worldwide spread. Numerous countries have implemented control measures related to international travel, including border closures, travel restrictions, screening at borders, and quarantine of travellers. This rapid review assesses the effectiveness of international travel‐related control measures during the COVID‐19 pandemic on infectious disease transmission and screening‐related outcomes.
Most people infected with SARS‐CoV‐2 have mild disease with unspecific symptoms, but about 5% become critically ill with respiratory failure, septic shock and multiple organ failure. An unknown proportion of infected individuals never experience COVID‐19 symptoms although they are infectious, that is, they remain asymptomatic. Those who develop the disease, go through a presymptomatic period during which they are infectious. Universal screening to detect individuals who are infected with SARS‐CoV‐2 before presenting clinically, could be an important measure to contain the spread of the disease. This rapid review aims to assess the effectiveness of universal screening for SARS‐CoV‐2 infection compared with no screening, and the accuracy of universal screening in people who have not presented to clinical care for symptoms of COVID‐19. Associated Cochrane Clinical Answer: What is the accuracy of symptom screening and elicitation of information about travel history and exposure to a known infected person for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection?
Coronavirus (COVID‐19) is a new virus that has spread quickly throughout the world. COVID‐19 spreads easily between people who are in close contact, or through coughs and sneezes. Most infected people suffer mild flu‐like symptoms, but some become seriously ill and even die. This rapid review assesses quarantine (alone or in combination with other measures) of individuals who had contact with confirmed cases of COVID‐19, who travelled from countries with a declared outbreak, or who live in regions with high transmission of the disease. Associated Cochrane Clinical Answers: What are the effects of quarantine for close contacts of people with confirmed COVID‐19?; What are the effects of quarantine for individuals traveling from a country with a declared COVID‐19 outbreak?; and What are the effects of quarantine plus other measures for controlling the spread of COVID‐19?
Reducing transmission of SARS‐CoV‐2 is a global priority. Contact tracing identifies people who were recently in contact with an infected individual, in order to isolate them and reduce further transmission. Digital technology could be implemented to boost manual contact tracing, with digital tools being grouped into three areas: 1) outbreak response; 2) proximity tracing; and 3) symptom tracking. This rapid review assesses the benefits, harms, and acceptability of personal digital contact tracing solutions for identifying contacts of an identified positive case of an infectious disease. Associated Cochrane Clinical Answer: During epidemics, how effective are digital contact tracing technologies for identifying secondary cases and close contacts?
Viral epidemics or pandemics of acute respiratory infections like influenza or severe acute respiratory syndrome pose a global threat. Antiviral drugs and vaccinations may be insufficient to prevent their spread. This review assesses the effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses. Associated Cochrane Clinical Answer: Can physical interventions help reduce the spread of respiratory viruses?
Handwashing is important to reduce the spread and transmission of infectious disease. Ash, the residue from stoves and fires, is a material used for cleaning hands in settings where soap is not widely available. This review assesses the benefits and harms of hand cleaning with ash compared with hand cleaning using soap or other materials for reducing the spread of viral and bacterial infections. Associated Cochrane Clinical Answer: Does hand cleaning with ash reduce the spread of viral and bacterial infections?
Nursing homes for older people provide an environment likely to promote the acquisition and spread of meticillin‐resistant Staphylococcus aureus (MRSA), putting residents at increased risk of colonization and infection. It is recognized that infection prevention and control strategies are important in preventing and controlling MRSA transmission. This review aims to determine the effects of infection prevention and control strategies for preventing the transmission of MRSA in nursing homes for older people. Associated Cochrane Clinical Answer: Does an education intervention in nursing homes help prevent the transmission of methicillin‐resistant Staphylococcus aureus (MRSA)?
In response to the spread of SARS‐CoV‐2 and the impact of COVID‐19, national and subnational governments implemented a variety of measures in order to control the spread of the virus and the associated disease. One setting affected heavily by these measures is the school setting. By mid‐April 2020, 192 countries had closed schools, affecting more than 90% of the world’s student population. In consideration of the adverse consequences of school closures, many countries around the world reopened their schools in the months after the initial closures. This review identifies and comprehensively maps the evidence assessing the impacts of measures implemented in the school setting to reopen schools, or keep schools open, or both, during the SARS‐CoV‐2/COVID‐19 pandemic, with particular focus on the types of measures implemented in different school settings, the outcomes used to measure their impacts and the study types used to assess these. Associated Cochrane Clinical Answer: What evidence is available on measures implemented in school settings to reopen schools and/or keep schools open during the COVID‐19 pandemic?
Infection control in healthcare settings
In epidemics of highly infectious diseases, such as Ebola, severe acute respiratory syndrome (SARS), or coronavirus (COVID-19), healthcare workers are at much greater risk of infection than the general population, due to their contact with patients’ contaminated body fluids. Personal protective equipment (PPE) can reduce the risk by covering exposed body parts. This review evaluates which type of full-body PPE and which method of donning or doffing PPE have the least risk of contamination or infection for healthcare workers, and which training methods increase compliance with PPE protocols. Associated Cochrane Clinical Answer: Which type of personal protective equipment (PPE), and which interventions to increase PPE use by healthcare workers, help reduce the spread of highly infectious diseases?
Many dental procedures produce aerosols (droplets, droplet nuclei and splatter) that harbour various pathogenic micro‐organisms and may pose a risk for the spread of infections between dentist and patient. The COVID‐19 pandemic has led to greater concern about this risk. This review assesses the effectiveness of methods used during dental treatment procedures to minimize aerosol production and reduce or neutralize contamination in aerosols. Associated Cochrane Clinical Answers: How does high‐volume evacuation (HVE) compare with no HVE or alternative dental suction for reducing contaminated aerosols during dental procedures? and How do antimicrobial coolants compare with one another or with placebo for reducing contaminated aerosols during dental procedures?
When new respiratory infectious diseases become widespread, such as during the COVID‐19 pandemic, healthcare workers’ adherence to infection prevention and control (IPC) guidelines becomes even more important. Strategies in these guidelines include the use of personal protective equipment such as masks, face shields, gloves and gowns; the separation of patients with respiratory infections from others; and stricter cleaning routines. These strategies can be difficult and time‐consuming to adhere to in practice. This rapid qualitative review identifies barriers and facilitators to healthcare workers’ adherence to IPC guidelines for respiratory infectious diseases. Associated Cochrane Clinical Answer: What are the organizational, environmental, and individual barriers and facilitators affecting healthcare workers’ adherence to infection prevention and control (IPC) guidelines for respiratory infectious diseases?
Healthcare‐associated infection is a major cause of morbidity and mortality. Hand hygiene is regarded as an effective preventive measure. This review assesses the short‐ and long‐term success of strategies to improve compliance to recommendations for hand hygiene, and to determine whether an increase in hand hygiene compliance can reduce rates of healthcare‐associated infection. Associated Cochrane Clinical Answers: What are the effects of multimodal campaigns to improve hand hygiene of healthcare workers? and What are the effects of performance feedback, education, and olfactory/visual cues on hand hygiene of healthcare workers?
‘Standard Precautions’ refers to a system of actions, such as using personal protective equipment or adhering to safe handling of needles, that healthcare workers take to reduce the spread of germs in healthcare settings such as hospitals and nursing homes. This review assesses the effectiveness of interventions that target healthcare workers to improve adherence to Standard Precautions in patient care. Associated Cochrane Clinical Answer: Does healthcare worker education improve adherence to standard precautions for controlling health care‐associated infections?
Meticillin‐resistant Staphylococcus aureus (MRSA) is a common hospital‐acquired pathogen that increases morbidity, mortality, and healthcare costs. Its control continues to be an unresolved issue in many hospitals worldwide. This review assesses the effectiveness of wearing gloves, a gown or a mask when contact is anticipated with a hospitalized patient colonized or infected with MRSA, or with the patient’s immediate environment. Associated Cochrane Clinical Answer: Do gloves, gowns, and masks reduce transmission of MRSA in the hospital setting?
Overgowns are widely used in newborn nurseries and neonatal intensive care units. It is thought that gowns may help to prevent the spread of nosocomial infection and serve as a reminder to staff and visitors to wash their hands before contact with the infant. This review assesses the effects of the wearing of an overgown by attendants and visitors on the incidence of infection and death in infants in newborn nurseries. Associated Cochrane Clinical Answer: Does gowning by attendants and visitors in newborn nurseries help prevent neonatal morbidity and mortality?
Respiratory hazards are common in the workplace. Depending on the hazard and exposure, the health consequences may include mild to life‐threatening illnesses from infectious agents, acute effects ranging from respiratory irritation to chronic lung conditions, or even cancer from exposure to chemicals or toxins. Use of respiratory protective equipment (RPE) is an important preventive measure in many occupational settings. RPE only offers protection when worn properly, when removed safely and when it is either replaced or maintained regularly. The effectiveness of behavioural interventions either directed at employers or organizations or directed at individual workers to promote RPE use in workers remains an important unanswered question. This review assesses the effects of any behavioural intervention either directed at organizations or at individual workers on observed or self‐reported RPE use in workers when compared to no intervention or an alternative intervention. Associated Cochrane Clinical Answer: Do educational interventions improve respiratory protective equipment (RPE) use in the workplace?
Hospital‐acquired infection is a frequent adverse event in patient care; it can lead to longer stays in the intensive care unit, additional medical complications, permanent disability or death. Prevalence of infection is particularly high in the intensive care unit, where people who are critically ill have suppressed immunity and are subject to increased invasive monitoring. Chlorhexidine is a low‐cost product, widely used as a disinfectant and antiseptic, which may be used to bathe people who are critically ill with the aim of killing bacteria and reducing the spread of hospital‐acquired infections. This review assesses the effects of chlorhexidine bathing on the number of hospital‐acquired infections in people who are critically ill. Associated Cochrane Clinical Answer: What are the effects of chlorhexidine bathing for preventing hospital‐acquired infection in people admitted to intensive care units (ICUs)?
COVID‐19 infection poses a serious risk to patients and – due to its contagious nature – to those healthcare workers (HCWs) treating them. If the mouth and nose of HCWs are irrigated with antimicrobial solutions, this may help reduce the risk of active infection being passed from infected patients to HCWs through droplet transmission or direct contact. However, the use of such antimicrobial solutions may be associated with harms related to the toxicity of the solutions themselves, or alterations in the natural microbial flora of the mouth or nose. Understanding these possible side effects is particularly important when the HCWs are otherwise fit and well. This review assesses the benefits and harms of antimicrobial mouthwashes and nasal sprays used by healthcare workers (HCWs) to protect themselves when treating patients with suspected or confirmed COVID‐19 infection.
Antimicrobial mouthwashes (gargling) and nasal sprays administered to patients with suspected or confirmed COVID‐19 infection to improve patient outcomes and to protect healthcare workers treating them
COVID‐19 infection poses a serious risk to patients and – due to its contagious nature – to those healthcare workers (HCWs) treating them. If the mouth and nose of patients with infection are irrigated with antimicrobial solutions, this may help the patients by killing any coronavirus present at those sites. It may also reduce the risk of the active infection being passed to HCWs through droplet transmission or direct contact. However, the use of such antimicrobial solutions may be associated with harms related to the toxicity of the solutions themselves or alterations in the natural microbial flora of the mouth or nose. This review assesses the benefits and harms of antimicrobial mouthwashes and nasal sprays administered to patients with suspected or confirmed COVID‐19 infection to both the patients and the HCWs caring for them.
COVID‐19 infection poses a serious risk to patients and – due to its contagious nature – to those healthcare workers (HCWs) treating them. The risks of transmission of infection are greater when a patient is undergoing an aerosol‐generating procedure (AGP). Not all those with COVID‐19 infection are symptomatic or suspected of harbouring the infection. If a patient who is not known to have or suspected of having COVID‐19 infection is to undergo an AGP, it would nonetheless be sensible to minimise the risk to those HCWs treating them. This review assesses the benefits and harms of antimicrobial mouthwashes and nasal sprays administered to HCWs and/or patients when undertaking AGPs on patients without suspected or confirmed COVID‐19 infection.
About this Special Collection
This Special Collection was developed by Lisa Bero (Senior Editor, Public Health and Health Systems), working with Toby Lasserson (Deputy Editor in Chief), Newton Opiyo (Associate Editor), Robin Featherstone (Information Specialist), and Monaz Mehta (Editor) in the Cochrane Editorial & Methods Department. Colleagues from the Public Health and Health Systems Network, Cochrane China Network, Cochrane Wounds, and Cochrane Acute Respiratory Infections Groups also provided input on the selection of reviews for this Special Collection.
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Cochrane Editorial and Methods Department (firstname.lastname@example.org)