As more people are being vaccinated around the globe, the matter raises the question of what one can or cannot do regarding social interactions around their unvaccinated friends and family as the pandemic still rages on.
More than 33 million people in the United King have already been administered their first Covid-19 vaccine dose, with just over 13.2 million adults receiving both doses, reports The Guardian.
Here is an experts' guide to etiquette for the newly vaccinated.
Don't assume you're protected until you've received both doses
The Centers for Disease Control and Prevention (CDC) in the United States announced this week that "fully vaccinated" people will gather indoors with other vaccinated people without masks or physical separation.
Two weeks after receiving a second dose, it considers people completely vaccinated. One should have some security before this, but not so much that they can afford to relax your guard.
Even once you've had two doses, you're not invincible
While Covid vaccinations are highly effective at preventing serious disease and death, Gabriel Scally, a visiting professor of public health at the University of Bristol, said that "it would be incorrect for anyone to believe that since they're completely vaccinated, that means they're fully protected from the virus." "We can still contract the disease and develop symptoms, and they can still spread it."
While the exact amount of transmission is unknown, recent Public Health England research shows that people who were infected at least three weeks after receiving their first vaccine dose were 38-49 percent less likely than unvaccinated people to spread the virus to those in their homes. However, transmission did occur in some situations.
Hugging another vaccinated person is unlikely to kill you – but it may lengthen the pandemic
According to the CDC, hugging two fully vaccinated people is healthy, but others advise caution. The more the virus is spread, the more likely new strains will arise and spread, potentially rendering vaccines ineffective and causing those variants to mutate further.
"It's great that the vaccines have an impact on transmission, because it means that once you get enough people immunised, you can drive down transmission, but on an individual level, it just doesn't work," said Prof Adam Finn of the Bristol Children's Vaccine Centre. "[Vaccinated] older folks can go and kiss everyone on the basis that they're highly unlikely to get seriously ill and die. But if they want to bring the pandemic to an end, they need to continue to take precautions just like everyone else."
If you do hug, be mindful of local infection rates
Close physical contact is likely to be safer if the number of infections in your local area are low. Places such as Shetland and the Western Isles have recorded zero Covid cases in the past week, whereas the infection rates in Derry City and Strabane, and Kirklees in West Yorkshire, currently stand at 83 and 72 cases per 100,000 people respectively. "If you're in the Western Isles, it would be safe to hug, but that's not necessarily true everywhere," said Scally.
It's also worth considering where you've been and who you've seen in recent days. If you've been highly sociable you're more likely to be infected.
Don't assume your peers have been vaccinated just because you have
"Often in conversations, you discover that people that you would assume would be vaccinated have reservations, and some people are not sharing whether they've been vaccinated or not," said Dr Nilufar Ahmed, a behavioural psychologist at the University of Bristol.
Indoor family reunions should be treated with caution
If you're confident that everyone has been fully vaccinated, a small group of you could gather indoors with relative impunity. However, you should be more careful when mixing with unvaccinated family members or friends. In Wales, such mixing will be allowed from 3 May. The CDC advises wearing a mask in such situations. Physical distancing and ventilation also reduce risks.
It's OK to insist everyone does a rapid Covid test as a precaution
Twice-weekly lateral flow tests have been rolled out across England. Asking people to take one before they meet at social gatherings can further reduce the risks. "For some people, that might be seen as being rude, but for others, it's the kind of reassurance that may be needed," Ahmed said.
For indoor public gatherings, physical distancing and masks are still essential
With larger crowds, the risks of transmission are amplified. So it is critical that people mask up and keep physically distanced in indoor public spaces such as shops, places of worship and theatres (when these open). If everyone in an audience or congregation were fully vaccinated the risk of transmission would be greatly reduced – but not entirely eliminated.
International travel is still risky for everyone
"International travel to regions with a high Covid-19 incidence should be treated with serious caution, as this brings with it a credible risk of importing new coronavirus variants of concern into the UK," said Prof Neil Mabbott, chair of immunopathology at the University of Edinburgh.
"If a fully vaccinated person were to become infected, symptomatically or asymptomatically, with one of these variants while travelling overseas, they could bring it into the UK where it could have potential to infect both unvaccinated and fully vaccinated individuals."
Outdoors is still safest, but wear a mask if it's busy
Many are looking forward to the return of outdoor events but closely crowded spaces are still risky. The CDC recommends that even fully vaccinated people wear masks at crowded outdoor events such as live performances, parades, or sports events. It is also worth considering how people arrived at such events, and whether this may have caused overcrowding on public transport, said Mabbott.
Just because your older relatives have been jabbed, doesn't mean you don't need to be
Younger people are less susceptible to serious illness and death from coronavirus, but plenty still end up in hospital or develop "long Covid". "There are plenty of young people who, even though they're only mildly ill, are very much affected for a long period," said Finn. Even if you think you've already had Covid, you could be reinfected.
Then there's the risk you pose to others. How many people need to be vaccinated to reach herd immunity is still uncertain, but the fewer who take up the offer of a vaccine, the more problems are likely later on. "As long as you've got approaching half the adult population non-immune, you've got the machinery for another big wave, and when that wave happens, it will find people who are vulnerable and kill them," said Finn. "It might not be your granny, but it will be someone else's granny."