Individual measures to limit transmission
In this article, Emilio Hornsey, Senior Infection Prevention and Control Nurse for the UK Public Health Rapid Support Team gives an overview of methods to reduce individual risk of infection. Many of these measures are widespread – why do you think this is? Consider also why guidance differs in different countries or contexts.
Infection prevention advice to individuals has the potential to reduce transmission of SARS-CoV-2 causing COVID-19, and if the advice is timely, clear and easy to understand it may also improve confidence in the response and give individuals a sense of control. It is important therefore that any advice to individuals is considered, evidence based, rational and coherent1.
Here follows some of the individual measures to protect against infection with SARS-CoV-2, that have been consistently recommended by WHO2 and others. In practice, most of these interventions are bundled together, so it is hard to know which are most effective.
Cough hygiene: A cough should be caught in a single use tissue, or the crook of the elbow. The tissue should be immediately disposed of and hand hygiene performed. Coughing into bare hands means they can become heavily contaminated; unless immediate and thorough hand hygiene is performed, they can become a vehicle for transmission. Cough hygiene can reduce, but not totally eliminate, droplets being released by a cough or sneeze3, 4.
Avoiding face touching: Avoiding face touching is a self-protective measure. The risk is that contaminated hands can contact mucosal surfaces and cause an infection. The extent of its role in transmission of infection has not been thoroughly investigated. People have been observed to touch their face 23 times per hour5 and more in times of stress and in some social groups6.
Physical distancing: Physical distancing includes a range of interventions which aim to reduce the number and closeness of physical contacts each person has. It may involve minimising physical contact through actions like hand shaking and avoiding large groups of people and crowded spaces. More extreme physical distancing measures may involve ”shielding” for vulnerable groups or population-wide restrictions, commonly termed “lockdown”. Physical distancing can protect both the individual and others around them. While the principle behind the intervention(s) is sound, it is difficult to assess the contribution of each individual element 7.
Self-isolation: Self isolation is a more extreme form of social distancing, it has been recommended for high-risk contacts and for those with mild symptoms who do not require medical care. The isolation of asymptomatic high-risk contacts is rational if there is strong evidence of pre or asymptomatic infection8. However mass isolation may have major social and economic effects9 so the risks and benefits should be balanced, and may be tailored according to risk, or consequences of, infection.
Hand hygiene: Frequent hand hygiene with either soap and water, or alcohol-based hand rub. Key moments are after using the toilet, coughing or sneezing, before preparing food or eating, after touching communal surfaces such as door handles and before touching your face. Hand hygiene should be thorough, to fully decontaminate all areas of the hands 10.
Face masks: The value of using these outside health care settings is debated 11 but face masks are one of the most visible features of individual response in many areas. The evidence for the protective effect of asymptomatic individuals wearing masks is weak 12 and they may change face touching behaviour as they become uncomfortable and need adjusting 13. There is evidence that wearing a mask reduces the droplet spray if individuals cough or sneeze 1, so they may protect other people from droplet contact from the wearer. To have any benefit face masks must be used correctly, whatever they are made from. The wearer must also ensure hand hygiene before donning (putting on) the mask, check it is clean, dry and undamaged, and ensure it covers the nose and mouth fully. Face masks should not be readjusted or touched once in place, and after doffing (taking off) hand hygiene should be performed and the mask laundered if it is made of cloth, or disposed of responsibly if it is paper.
Other advice (less consistently seen) includes:
Avoiding wet/live meat markets: This is only relevant in areas where these exist. Many early cases were associated with the Huanan seafood market for this outbreak14 but it is not established that this is where zoonotic transmission (spread from animals to humans) occurred. Without evidence of multiple events where zoonotic transmission of SARS-CoV-2 has occurred in wet/live meat markets, this measure won’t affect the course of this outbreak, but it could reduce the risk of a similar future emergence.
Quarantine with active health monitoring on arrival into the country: This requires good public health infrastructure to identify and follow new arrivals and support basic needs (food, accommodation) as if these are not met people will not be able to maintain quarantine.
Avoiding close contact with anyone who is sick: This is a specific element of physical distancing but will be harder to adhere to for people with caring responsibilities. Especially in countries who have a policy of household isolation of people with mild disease.
Not spreading rumours:17 This advice acknowledges the risks associated with misinformation, as described in the article on risk communication and community engagement in Week 1.
Regular household surface disinfection:18 Shared areas and high touch surfaces present a risk of facilitating transmission of SARS-COV2. Good home hygiene, involving regular environmental decontamination may reduce the risk of transmission within households.
Avoiding spitting in public:19 In some cultures public spitting is much less socially acceptable in general so a specific injunction isn’t required. However where it is, spitting should be strongly discouraged.
The same interventions may be presented in different ways20, 21. For example, in more individualised cultures the explanation may be more rooted in self-protection, whereas in collectivist cultures the justification may be rooted in protection of others.
You can find some useful answers in the FAQs for this Step, so do have a look at these, and in the See Also section there are links to guidance.
© London School of Hygiene & Tropical Medicine 2020