Some of the media coverage of the breakthrough cases seems excessive given how rare it actually is.
This is not directly related, but it looks like Chile is finding out the hard way that the first dose of the Sinovac vaccine is not (by itself) very effective.
>>>On Friday, Chilean authorities released the results of a study of 10.5 million people, showing the vaccine was 16% effective against infection after one dose and 67% effective after a second dose. The study also found it to be 80% effective in preventing death from Covid-19 two weeks after a second dose.
That is lower than the vaccine made by Pfizer Inc. and BioNTech SE, for example. Research published in February in the Lancet medical journal found that one dose of the Pfizer and BioNTech vaccine was 85% effective in preventing symptomatic disease 15 to 28 days after being given, according to a peer-reviewed observational study of about 9,000 people in Israel.
Research also found the
vaccine’s efficacy to be 91.3% up to six months after getting the second dose, Pfizer and BioNTech said.<<<
https://www.wsj.com/articles/first-dose-of-chinese-covid-19-vaccine-offers-little-protection-chile-learns-11618775502