Despite having very few cases overall we've had a few here where the only link is public transport (buses specifically). Far more from other causes like being family members or workmates, but those are also a lot easier to contain.
China's vaccine is fine, at least for efficiency. The Brazil study is being- probably deliberately- misinterpreted, often by those who should know better*. The issue is similar to one there was a brief discussion about a few pages ago about what the efficacy of a vaccine means, practically, and the difference between SARS-CoV2 and Covid19. Most vaccines aren't of the smallpox type eradication sort.
Despite everyone talking about 'immunity' as a shorthand that's not what they're talking about when it comes to how well the vaccine works. In part because that isn't really how the human immune system works. The- pretty much fake news- headlines about China's vaccine having a ~50% effectiveness are an example. It's 50% effective, if you include asymptomatic and very mild infections. Sounds kind of bad, however, it's 100% effective against severe covid19. You can still be infected by SARS-CoV2 post vaccination, but you won't get severe covid19 from it, and your chances of getting covid19 at all are reduced ~80%. It's reduced the chances of getting infected, and the effects of the infection.
To illustrate the point, the highly effective Pfizer vaccine's efficacy drops precipitously if you do the analysis the same way that was done to the sinapharm one, ie include everyone reporting mild symptoms and those with positive PCR but no symptoms. Indeed, it actually has a worse efficiency than sinapharm in that case. It's irrelevant in both cases, because an infection that causes minimal harm might as well not exist. 'Covid19' defines a set of symptoms caused by the SC2 virus, severe enough to kill. If you don't/ didn't have the symptoms you don't have the disease, what you have is another coronavirus contributing to the mix of various viruses that causes the 'common cold'.
*I made fun previous of the BBC for their utterly partisan coverage of Sputnik vs AZOxford compared to how the results turned out and they're now repeating the 50% effective claim acritically as well. Useless coverage is part of the reason we end up with antivaxxers, and by and large the coverage has been a masterclass in Western Exceptionalism instead- indeed, as mentioned yesterday, the Chinese vaccine being indemnified is used to build suspicion without mentioning the context that the western vaccines are indemnified in the same way too.