2. It's really curious to see people saying, on the one hand, that they're uncertain about a vaccine because of some unexpected long-term impacts, and then saying on the other hand that they're unconcerned about unexpected long-term impacts from a brand new and as-yet-poorly-understood disease. There are still a lot of question marks about covid-19 and researchers are still discovering far more "quiet" impacts in apparently healthy individuals, including blood clots and pericarditis.
2a. Overall though I'm in favor of anybody avoiding this vaccine that wishes to. The disease would continue to disproportionately affect the populations of people who believe it's a hoax, or believe it's not a serious health risk, or believe it's a conspiracy, or believe the vaccine is a conspiracy, or believe that vaccines in general are conspiracies -- and we could do with fewer of those people.
3. As two other people have already pointed out, the researchers have only been cautious about not stating something that they don't know to be factual. It's funny: when researchers are cautious, people read too much into it and draw bad conclusions, and that leads to the kinds of research press releases that other people then criticize for making statements unsupported by evidence. Researchers have repeatedly stated in various media that there's no reason for them to expect people to be infectious after taking the vaccine, they merely haven't tested for this specifically.
4. The people they're talking about here are the sort that need to carry an epi-pen with them wherever they go. If you are one of those people, then yes, at this time there's an uncertain amount of risk associated with these vaccines. The situation is still developing and there should be better information available as the vaccines are distributed.