Mask-Wearing as a Cognitive Cue

Wariness of asymptomatic infectious disease is cognitively unnatural.

Posted Mar 03, 2021 | Reviewed by Ekua Hagan


  • Fifty-nine percent of COVID-19 disease transmission has arisen from people who did not show symptoms.
  • Those infected who are asymptomatic do not trigger other people's natural avoidance behaviors.
  • Mask-wearing and other safety precautions can help us all remember to stay vigilant.

That COVID-19 can go completely undetected in people who are asymptomatic has served only to complicate this calamitous year. As Angela Rasmussen of the Center for Global Health Science and Security at Georgetown University notes, asymptomatic cases are when people are infected with the virus, SARS-Cov-2, but do not have the disease, COVID-19. A recent study in JAMA Network Open suggested that 59% of disease transmission has arisen from people who were either presymptomatic (35%) or asymptomatic (24%).

The failure to understand the infectiousness of asymptomatic people has consistently complicated the implementation of effective public health measures, in particular. Ample evidence over the past months indicates that when people look and feel fine and when the people around them look and feel fine, they may be reluctant to adopt sound public health measures such as wearing masks and social distancing. As I argued here, because asymptomatic people will not cue humans’ natural avoidance behaviors in response to the presence of infectious agents in their environments, people, who only trust their intuitions or who tout common sense, will be more likely, all else being equal, to make false-negative errors in their judgments about the dangers of infection from those around them. In short, fearing asymptomatic infectious disease is cognitively unnatural. It requires intellectual effort.  

Vaccines Preventing Disease vs. Vaccines Preventing Infection

The primary short-term aim of the new vaccines is to prevent or diminish the impact of the disease, COVID-19. Preventing the disease, however, is not the same thing as vaccines preventing infection with the virus SARS-CoV-2, which causes COVID-19. (Vaccines that prevent an infection produce what is known as “sterilizing” immunity.) This is just to say that the new vaccines may not eliminate the possibility of people infected with SARS-CoV-2 who are asymptomatic.

Crucially, as Rassmussen has emphasized, it does not follow that the new vaccines are impotent.  That is because they have generally proven extremely effective at preventing disease. They prevent grave illness and death if a fully vaccinated person has become infected with the SARS-CoV-2 virus. Not only do the vaccinated people avoid becoming seriously ill, but increasing the numbers of vaccinated people reduces the number of patients requiring hospitalization, which frees up staff and resources to aid those patients who are in dire need.

Vaccines that prevented infection would certainly protect people against the disease. Scientists do not yet know how well the current vaccines prevent the infection, their impressive prevention of the disease notwithstanding. Although preliminary evidence indicates that the Pfizer and Moderna vaccines appear to be cutting the rate of transmission of the infection and of asymptomatic cases (and it is a reasonable expectation that they will), scientists, at least currently, apparently do not have what they regard as sufficient data to draw that conclusion definitively about any of the vaccines yet (crucially, the operative word is “yet”).

3 Reasons for the Vaccinated Continuing to Comply With Public Health Measures

Experts have generally affirmed that the vaccinated should continue mask-wearing, social distancing, and avoiding crowded indoor spaces, not only as a symbol of collective solidarity in fighting the pandemic, encouraging the yet-to-be-vaccinated to remain vigilant about such public health measures, but more importantly, because even the vaccinated may still be able to infect other people.

These highly effective vaccines against disease (and probably against infection as well) do not appear to eliminate asymptomatic cases completely. The cognitive unnaturalness of asymptomatic infectious disease suggests a third reason why the vaccinated should continue to comply with these public health measures. Doing so — for example, wearing a mask — is more likely than not to cue others’ natural precautionary responses, which should lead to behaviors that help to decrease the transmission of the disease.


Johannsson, M. A. et al. (2021).  SARS-CoV-2 Transmission from People without COVID-19 Symptoms.  JAMA Network Open.  4(1):e2035057. doi:10.1001/jamanetworkopen.2020.35057