Covid 19 is in the same category as Rhinovirus aka the common cold so how exactly will any vaccine be effective?

How long is a piece of string?

We do not know the answer to this question regarding COVID-19. At the moment there is no known effective and safe vaccine. They are all currently the subject of ongoing research.

All viruses mutate but not all mutate to the extent that they become resistant to a vaccine.

One of the reasons we have no vaccine for the common cold is the sheer number of viruses that can cause it.

We have an effective vaccine against measles. We have vaccines against influenza-causing viruses. Due to mutation a different vaccine is developed each year. Progress on a vaccine for HIV is looking promising.

First, we need to develop a vaccine that will be effective in stimulating an immune response to SARS-CoV-2, the virus that causes COVID-19. At the moment we do not know how long the immunity it provides will last. It may require an initial inoculation and then one or more boosters. That may be all that is required. Alternatively, depending on how the virus mutates, if it does, it may be necessary to vaccinate people on an annual basis as is required for influenza.

Secondly, the vaccine needs to be safe. In other words it must produce few side effects in a small number of people and these must be tolerable.

Thirdly, enough people will need to be vaccinated. This is required so that we get herd immunity. With herd immunity there will be so few people the virus can infect that infections will be few. Also, herd immunity is important to protect people who for a variety of clinical reasons will not be able to have the vaccine. Hopefully, enough people will be sensible and get vaccinated if a vaccine becomes available and not too many people will listen to the ignorant and dangerous idiots who are opposed to vaccination.

I suspect there will be high uptake in countries like those in Scandinavia where society is very community orientated. Also, in other countries with a record of high uptake such as the UK; although, here, more idiots are following the stupid path of not being vaccinated. I am not sure what vaccine uptake is like in countries like the USA. I would suspect it is lower because there people focus more on themselves rather than have high concern for the community like Scandinavians. I would also be interested to know what vaccine uptake is like in places such as Australia, Canada and New Zealand. In the case of the latter, I suspect uptake would be high based on how the New Zealand population responded to its government's requests to behavioural changes to reduce COVID-19 from spreading.

same as the flu--it mutates every year as well, a vaccine would be similar