An editorial in The Lancet Microbe published May 20th 2021 discusses this important subject.
The US Centre for Disease Control and Prevention, the CDC, changed its recommendation on mask use in a move that came as a surprise to many including US federal and local administration officials, scientists and members of the public.
Individuals who are fully vaccinated are now allowed to resume activities that they did before the COVID-19 pandemic. This includes to socially interact without wearing masks or physically distancing, including indoors, with the exception of on public transport, in healthcare facilities and in settings where different federal, state or local regulations on mask use supply.
This is of course only pertinent to the United States of America.
No restrictions are in place on the number of people gathering.
By contrast, individuals who are not fully vaccinated must continue to follow the previous guidance such as wear a mask, keep a 1.8 metre distance from others and avoid crowds or poorly ventilated places.
This relaxation was widely celebrated with US President Joe Biden calling it a milestone in the fight against COVID-19, but it also sparked furious debate.
On paper the editorial argues that the new recommendations are logical.
Real world data confirms the published interim trial data that vaccines approved in the United States prevent serious disease and death and further indicate that they reduce the risk of transmission of SARS-CoV-2.
Therefore, when not wearing a mask, fully vaccinated individuals are at low risk of both getting and spreading COVID-19.
However, there are some considerations to be considered.
First, the new guidelines create a tiered society based on vaccination status, for those who are not fully vaccinated having reduced liberties compared with fully vaccinated people.
Indeed, part of the rationale behind the change in guidelines is the hope that reduced restrictions will incentivise vaccine hesitant people to get vaccinated.
Although this strategy might work in the case of individuals who do not plan to get vaccinated because they are not concerned about getting infected with SARS-CoV-2.
For young people who rarely develop symptoms, it is unlikely to change the attitude of those who do not believe in the efficacy of the vaccine, who fear it side effects, who cannot afford to take time off work to get it or those whom are unaware that the vaccine is free.
Second, it is unclear whether and how the new recommendations will be enforced.
It seems conceivable that people who were against wearing masks in the first place will take the chance to stop wearing them altogether, regardless of their vaccination status.
If such an attitude became widespread, it could lead to new outbreaks and increases in the number of COVID-19 cases, hospitalisations and deaths, particularly in areas where vaccination rates are currently low but transmission is ongoing.
Furthermore, it will put an increased risk on individuals who cannot be vaccinated for example, health reasons and those who even when vaccinated might not be fully protected such as individuals on immunosuppressive drug regimes.
Finally, at the time of change in CDC recommendations, about 36% of US citizens have been fully vaccinated.
In global landscape, that is an impressive achievement, but it is still far from the proportion of vaccinated population thought to be necessary for herd immunity, which is 60-70%.
Cases of infection with the SARS-CoV-2 variant first identified in India, B.1.617, have been reported in the USA.
Although insufficient data is available on its transmissibility and immune evasion potential, the rapid increase in infections with this variant in other countries such as India itself and the UK suggests it might be highly transmissible.
If this is indeed the case, with the majority of the US population not fully protected, the risk of a new spike in infections should not be underestimated.
The editorial argues that the decision to grant different degrees of liberty to different subsets of the population appears premature.
They argue that waiting a few additional weeks would have allowed for a substantially larger fraction of the population to be immunised.
Perhaps waiting could have granting a few more liberties to all such as no masks in outdoor spaces, were a minority of infections occur, but continue to use the masks and physical distances in indoor settings would have been easier to control and more importantly fairer.
The London General Practice considers that until such time that the majority of the UK population is vaccinated, facemasks should be worn in all indoor situations.
Dr Paul Ettlinger
BM, DRCOG, FRCGP, FRIPH, DOccMed