So they wasted time, money and resources to vaccinate them

Who do you think this "they" is? Do you think it was the same people all motivated to do the exactly the same things? You obviously have no idea how massive bureaucratic nation states are run.

There was thousands of concentration camps across Germany and the occupied territories. Some of these camps were run by virulent antisemitic Nazis, some by people with no particular grudge against Jews, some by incompetents and drunkards, some by sadists and disciplinarians, some by relatively ordinary men who were just doing a job, some by bureaucrats who followed the rules exactly and some by people who treated the rules as guidelines. The camps were controlled by different branches of the Germany state, for different reasons, by people competing for resources and political power.

Some camps were work camps, with the aim to work the prisoners to death but not too quickly as they wanted to get useful work done too. Sometimes, in the effort to encourage the prisoners to work harder, they were offered rewards for hard work like prostitutes, cigarettes and beer.

Some camps were temporary holding camps for prisoners in transit, where it would be inconvenient and annoying for too many prisoners to die.

Some camps were run by the Gestapo to interrogate people for matters of national security and didn't have the capacity to take more than a few dozen people at a time, for the Gestapo's close personal attention.

At least one camp was a show camp, deliberately set up to fool the Red Cross and dispel rumours of ill-treatment.

A few camps were detention camps for favoured prisoners and detainees who would be deported to countries Germany didn't want to offend, or swapped for Germany prisoners.

Most camps were concentration camps, set up to hold people while the government decided what to do with them (put them to work, deport them, kill them).

Only a few were death camps designed for the explicit industrial scale murder of as many people as possible as quickly as possible.

Not only were the camps explicitly designed for different purposes, but Hitler's overall objectives changed over the twelve years he held power. The actual death camps themselves only ran for about 18 months or so, between the time that the Nazis felt that they had to exterminate all of Europe's Jews immediately and not wait for the end of the war, and the time that they feared that they might lose the war and the death camps might be discovered.

Expecting every camp to be run exactly the same way, with precisely the same policies and conditions, is as mad as expecting every single prison in the USA (from the highest security Supermax to the local sheriff's lockup in a town of 300 people) to be identically run with identical conditions.

except for the millions of "survivors" of course.

Even German efficiency has limits as to how many people it can kill in a day. Hitler was no Thanos to snap his fingers and disintegrate them all instantly.

Aside from the millions of Jews, the Nazis had more millions of political prisoners, Soviet prisoners of war, common criminals, "social undesirables" and others going through the concentration camp system. The prisoners in the work camps couldn't be killed too quickly as that would defeat the purpose of using them for slave labour. There were efficiency bottlenecks everywhere, it was in the middle of a war. Despite the hunger, the disease, the maltreatment, the death marches and the extermination camps, yes, many people did survive.