Jefferson_et_al-2023-Cochrane_Database_of_Systematic_Reviews
P L A I N L A N G U A G E S U M M A R Y
Do physical measures such as hand-washing or wearing masks stop or slow down the spread of respiratory viruses?
Key messages
We are uncertain whether wearing masks or N95/P2 respirators helps to slow the spread of respiratory viruses based on the studies we assessed.
Hand hygiene programs may help to slow the spread of respiratory viruses.
How do respiratory viruses spread?
Respiratory viruses are viruses that infect the cells in your airways: nose, throat, and lungs. These infections can cause serious problems
and affect normal breathing. They can cause flu (influenza), severe acute respiratory syndrome (SARS), and COVID-19.
People infected with a respiratory virus spread virus particles into the air when they cough or sneeze. Other people become infected if they
come into contact with these virus particles in the air or on surfaces on which they land. Respiratory viruses can spread quickly through a
community, through populations and countries (causing epidemics), and around the world (causing pandemics).
Physical measures to try to prevent respiratory viruses from spreading between people include:
· washing hands often;
· not touching your eyes, nose, or mouth;
· sneezing or coughing into your elbow;
· wiping surfaces with disinfectant;
· wearing masks, eye protection, gloves, and protective gowns;
· avoiding contact with other people (isolation or quarantine);
· keeping a certain distance away from other people (distancing); and
· examining people entering a country for signs of infection (screening).
What did we want to find out?
We wanted to find out whether physical measures stop or slow the spread of respiratory viruses from well-controlled studies in which one
intervention is compared to another, known as randomized controlled trials.
What did we do?
We searched for randomized controlled studies that looked at physical measures to stop people from acquiring a respiratory virus infection.
We were interested in how many people in the studies caught a respiratory virus infection and whether the physical measures had any
unwanted eects.
What did we find?
We identified 78 relevant studies. They took place in low-, middle-, and high-income countries worldwide: in hospitals, schools, homes,
offices, childcare centers, and communities during non-epidemic influenza periods, the global H1N1 influenza pandemic in 2009, epidemic
influenza seasons up to 2016, and during the COVID-19 pandemic. We identified five ongoing, unpublished studies; two of them evaluate
masks in COVID-19. Five trials were funded by the government and pharmaceutical companies, and pharmaceutical companies funded nine trials.
No studies looked at face shields, gowns, and gloves or screening people when they entered a country.