The studies that got the vaccines approved in the first place had to show that they were effecitive for all adults. I'm sure that with some digging it should be possible to find the data split by age group.
More recently, we've also gotten data for many vaccines showing that they're also effective for children and adolescents.
Lastly, another important group is the elderly. Some studies suggest that they respond more poorly to the vaccine and that the protection may last a shorter time. In response, many countries have prioritized the elderly for receiving booster shots (3rd dose).
>More recently, we've also gotten data for many vaccines showing that they're also effective for children and adolescents.
This is my principal area of concern. If I recall correctly, the studies that were submitted to FDA for approval for young children did not show improvement in hospitalizations or deaths, in fact there was not a single death in any of the groups, rather they relied on showing the jabs successfully produced antibodies (a much lower standard).
> did not show improvement in hospitalizations or deaths
Well, it's not surprising that there would be fewer deaths in children. We'd need a much larger study and I expect that this data will become available now that the vaccines are started to be more widely distributed.
> rather they relied on showing the jabs successfully produced antibodies (a much lower standard)
IIRC the study also found that the vaccine was effective at preventing infections.