More than 3.76 billion people worldwide have received a dose of a Covid-19 vaccine, which equates to about 49 percent of the population.

General practitioner, medical researcher, and founder of PrimeHealth Clinical Research, Iris Gorfinkel, M.D., told Bored Panda that 50% is an incredibly exciting number that just a year ago would have seemed virtually impossible.

"Now that we have arrived at almost the impossible, it's tempting to let our guard down, to let go of mitigation, to let go of masks and social distancing, to forget high-end hygiene. But there's a serious problem with that. And that's delta," Gorfinkel said.

"It's more than two times as infectious as the original variant had been. Because of that, instead of 70% of people being vaccinated to achieve herd immunity, we now need 90%."

Herd immunity is the level at which the disease will finally stop spreading. That means about 9 out of 10 people have to be vaccinated in the whole world if we want to get rid of Covid-19, including everyone, not just the ones who are eligible for the shot, which currently are 12 years old and over.

"We're not anywhere near that," Gorfinkel said. "Am I optimistic? Absolutely, because who would have even thought we'd have a vaccine [that fast?] It's exciting, but we still have a long way to go. And the answer will ultimately be vaccination, along with mitigation. In other words, we can't let go of our masks, we have to continue doing hand hygiene, we have to understand that this is a disease that transmits naturally through large droplets, but through aerosols as well — it hangs around in the air, like cigarette smoke, and it has to be taken seriously."

The doctor agreed that vaccine passports are a hot topic. "Bottom line is, they work, and they work very well as a public health tool."

"The first country to have gotten into this was Israel and boy, did they teach a wonderful lesson. Israeli health authorities basically sat down and asked themselves, 'do we use a carrot or do we use a stick?'"

"A carrot approach would be a vaccine passport, a stick approach would be mandating that everybody gets vaccinated. So rather than mandating it, they basically said, 'Fine, you want to go to the gym, you want to go to a movie theater, you want to go to a restaurant, you have to be vaccinated.' And in a way, they were also offering something in return for getting vaccinated. And it worked stunningly well."

As Tim Dare, Professor of Philosophy at the University of Auckland, and Justine Kingsbury, a Senior Lecturer in Philosophy at the University of Waikato, pointed out, the central concern is often that vaccine passports will cause or exacerbate inequality because access to a passport relies on access to vaccines, and access to vaccines has been unequal.

"Internationally, citizens of some countries are more likely to have access to vaccines – and so to vaccine passports – than citizens of other countries. And within countries, some individuals and groups are more likely to have access to vaccines than others," they wrote in The Conversation.

"Firstly, the need to contain Covid-19 justifies the significant restrictions of important liberties in lockdowns," they said. "But to the extent that vaccines work, that justification doesn’t apply to someone who has been vaccinated. The justification for curtailing liberties has gone (or at least, given the possibility of breakthrough cases, been considerably weakened), so for the vaccinated, the curtailment should go too."

"Secondly, distinguishing between people on the basis of their [Covid-19] immunity may be discrimination, but it's not obvious it is unjustified discrimination. Whether someone is vaccinated or not is arguably legitimate grounds for discrimination. The unvaccinated (for whatever reason) pose a greater risk to others than the vaccinated. They are also more likely to suffer severe symptoms if they get Covid-19."

"Thirdly, one reason to tolerate inequality is that sometimes it improves the position of the disadvantaged," Dare and Kingsbury added. "We might tolerate doctors' high incomes, for example, if the promise of a higher income led people to study medicine and we believed a good supply of doctors benefited the worst-off members of our community."

Vaccine passports might work the same way — they help get the economy going, so the government can support those still locked down. Plus, they're also an incentive to vaccinate, and high vaccination rates are good for everyone. Even the unvaccinated.

Iris Gorfinkel agrees that if a person is pinned down to the ground to receive a vaccine, that would be violating their rights. But if they're turned away from a movie theater or the gym during a pandemic because they haven't had a shot, it's a whole other thing.

"This is balancing the rights of those in a democracy to protect people, just like people don't have a right to smoke in a public area. You know, it's like my older patients ask 'what gives a person a right to go into a supermarket without a mask?'. We live in a society in which we need to get along with one another. And this isn't meant to separate out people, but rather to allow us to live together in peace."

Expanding on what Dare and Kingsbury have said, the doctor highlighted that vaccine passports work for the population, not the individual. But that's exactly what we need right now.

"They keep down the number of Covid-19 cases, hospitalizations, ICU visits, and deaths to an absolute minimum. Is this an absolute one size fits all? Of course not. And I do not want to create a divide between the vaccine-hesitant and those who get vaccinated ... [but] I'm deeply concerned about the divisive nature that's emerging from this debate."