Re: Not "divisive and discriminatory", but essential
Also, there's another point, which is that some people don't have a choice. They can't be vaccinated. Usually due to other medical coniditions that make them more vulnerable. We include them in the list of those who have been vaccinated, out of fairness. They may at times want to avoid public interactions, due to the extra risk to them - but we leave that choice to them.
However not getting vaccinated without medical cause, puts them at risk.
There are specific cases, where we should insist on vaccine certificates. Such as care/nursing homes - and probably the NHS in general. For example, when I last looked at the stats we'd only vaccinated 96% of people over 80, as opposed to 99% of the groups down to 65. This isn't because of some failure in the vaccine programme, it's that larger numbers of that age group can't have the vaccine. Therefore we're going to need to insist on the highest level of protection from those around them.
I believe we already insist in the UK that surgeons have the hepititis vaccine, but not other healthcare workers, because the transmission risk is much lower.
We're also going to need a vaccine certificate/passport/thingymajig of some kind for going abroad, since whatever our society may decide, other governments still get to tell us what to do once we land in their airports.
So this is basically inevitable.
There is also an almost philosophical argument about what vaccines are. Some people see a vaccine as just another medical treatment, something you individually choose whether you want, or are going to get. Something that you take to protect you.
But another way to see vaccines, is as a public good - as a way of protecting whole societies. Sometimes these interpretations can conflict. For example refusing to accept children into school if they've not been vaccinated (or can't be) - as happens in some countries.
For a much criticised example of this conflict: The UK chose to change the dosing regimes, early in the vaccine rollout. That was the JCVI, which is a joint government committee of epidemiologists, immunologists and other public health bods. They chose to extend the gap between vaccine doses. Fine in the case of the Oxford AstraZeneca one, which had been tested in both ways, but more problematic in the case of the Moderna and Pfizer/BioNTech ones, which hadn't. It's later been shown that they got that dead right, that increasing the dose intervals of those vaccines doesn't have a detrimental effect on levels of immunity - and may even improve it.
But the point was they were actually taking a small, but calculated, risk at the time. They were very slightly increasing the risk to those getting vaccinated, but doubling the number of people in the high risk groups that they could therefore vaccinate. And therefore massively decreasing the risk for those people - which is a trade-off that's probably saved a few thousand lives - and if other global bodies had followed their example would have saved tens of thousands of lives around the world.
These trade-offs are important, but harder to understand. Even one of our main doctors' professional bodies publicly criticised the decision at the time. Though they may have partly been out of habit, at criticising the government, but it was also due to not having fully understood the question.
i.e. in the case of vaccines, it's not all about you. Sometimes you have to accept a very slightly higher risk, in order to protect others. But in turn, that very tiny extra risk will be outweighed even to yourself. by the herd immunity of those around you protecting you from the same disease.