On 3rd March 2020, the UK government published guidance on its coronavirus (covid-19) action plan. As the number of cases reported in the UK continues to rise, identifying strategies for delaying an epidemic has become ever more important. One topic in particular is currently under scrutiny: the handshake. In the UK, as elsewhere, this has become a topic of media interest, although avoiding handshakes is not official policy. Other countries, including China, France, Australia, Germany, and the UAE, have recommended against hand shaking or other traditional forms of greeting such as kissing on the cheek (France) and the “nose to nose” greeting (UAE). However, the extent of the risk of transmission of infectious illnesses through handshaking is unclear.

While shaking hands is a conventional greeting internationally, it may contribute to the spread of viruses and bacteria, although there is a dearth of research quantifying the risk of transmission. Banning hand shaking has been proposed in some healthcare settings and as “common sense” on cruise ships (where infection outbreaks are a particular risk). Alternative greetings which reduce contact time and surface area of contact have been proposed, with some, such as the open-hand wave, placing the right hand over one’s heart, head bowing, or the Namaste gesture (similar to the Thai wai), removing the need for physical contact altogether. Although some of these gestures convey slightly different meanings and should be used with sensitivity, they have the potential to reduce person-to-person transmission of infectious illnesses. Even alternative greetings which reduce, but do not remove, physical contact may have the potential to reduce transmission compared to handshaking. For example, the fist bump and giving a high five have been shown to significantly reduce transfer of bacteria compared to handshaking.

In addition to any direct effects on transmission, avoidance of handshaking may also have potentially important benefits in terms of promoting and maintaining better hand hygiene habits. Emotion is one of the most powerful drivers of behaviour and operates automatically, without the need for conscious effort. Hygiene behaviours are driven by a fundamental emotion of disgust at the prospect of contamination. An effective way of prompting and motivating people to engage in more handwashing is to increase emotional awareness that hand contact with other people (and the things they have touched) results in contaminated hands. Conversely, an important barrier to frequent handwashing is concern that excessive attention to hand hygiene breaches social norms and will be perceived as obsessive. If appropriately communicated, socially sanctioning the avoidance of hand-to-hand contact may convey the message that attention to hand hygiene is socially responsible and important for protecting against infection transmission.

Barriers to adopting such alternative forms of greetings include public doubts and lack of conclusive evidence about the need to reduce contact, concern about appearing rude, and the different cultural connotations of some suggested replacements. But attitudes towards the handshake may change during major disease outbreaks. During the H1N1 pandemic, 24% of people surveyed in New York State interpreted “avoiding sick people” as avoiding physical contact including shaking hands, hugging, kissing, and touching other people. In the UK, however, only 10% of the population reported avoiding handshakes. This may reflect the deeply ingrained nature of the handshake in British society, with avoidance of hand shaking and physical contact such as hugging and kissing being significantly lower during the 2009 pandemic in the UK than in Argentina, Mexico and the USA. 

It is important to quantify the potential impact that avoiding handshaking could have on infectious disease transmission. Nevertheless, if the handshake is to be discouraged during the covid-19 outbreak, clear messaging from public health officials will be required. In previous incidents, receiving information from a physician and greater understanding of virus transmission were associated with reducing physical contact, including handshaking. Leading by example will also be key: politicians and celebrities will need to visibly avoid handshaking and adopt alternative greetings. Finally, a reversal of the rules of etiquette may be required, to make it impolite or socially awkward to proffer a hand. Introducing a “hands-free” lapel badge or workplace policies could help to support any such public health policy. 

Louise E. Smith is a post-doctoral researcher in the NIHR Health Protection Research Unit of Emergency Preparedness and Response at King’s College London. Twitter handle: @louisesmith142

Lucy Yardley, School of Psychological Science, University of Bristol.

Susan Michie is Professor of Health Psychology and Director of the Centre for Behaviour Change at University College London and a member of the Scientific Pandemic Influenza Group on Behavioural Science (SPI-B): 2019 Novel Coronavirus (Covid-19).

James Rubin, Reader in the Psychology of Emerging Health Risks, King’s College London. 

Funding statement: Smith and Rubin are affiliated to the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Emergency Preparedness and Response at King’s College London in partnership with Public Health England (PHE), in collaboration with the University of East Anglia and Newcastle University [@EPR_HPRU]. Rubin is also supported by the UK Public Health Rapid Support team, funded by the United Kingdom Department of Health and Social Care. Yardley is partly supported by NIHR Applied Research Collaboration (ARC)-West, NIHR Health Protection Research Unit (HPRU) for Behavioural Science and Evaluation, and the NIHR Southampton Biomedical Research Centre (BRC). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, the Department of Health and Social Care or Public Health England. Michie is affiliated to the National Institute for Health Research Behaviour Science Policy Research Unit at University College London.

Competing interests: We have read and understood BMJ policy on declaration of interests and declare that we have no competing interests. 

Authors’ contributions: LS proposed the correspondence and wrote the first draft. All authors contributed to subsequent drafts.