how do you explain why Chile has more than half of its population vaccinated and the cases do not stop growing? Because what is happening there seems to contradict what the studies you link say.
Unknown, I haven't looked into it. Geographical proximity to Brazil and hence the Brazilian variant may be a factor. Might also depend on whether the vaccine was stored and transported properly - could be a factor given the extreme geography of the country. Might also depend on any lifting of lockdowns, and people becoming infected in the several week window before the vaccine starts to really take effect in the body. As I say though, these are guesses.
Okay, I've now done a little research. The British Medical Journal have
some data on it. Apparently the main vaccine used in Chile is Sinovac's CoronaVac... which appears less effective than the British AZ vaccine on a single dose basis (and the Chileans who have been vaccinated have overwhelmingly only had a single dose). Looks disturbingly like rich nations get the best vaccines, poorer nations are forced to choose from whatever is left, as you might anticipate:
A study published by researchers at the University of Chile on 6 April, in which Cortés was not involved, found that the CoronaVac vaccine was 56.5% effective in preventing infections two weeks after a second dose but only 3% effective after a single dose
Also it is considered
likely (anecdotal unless someone has seen the figures?) that the Brazil variant is a contributor:
Infections in Chile are also likely being driven by the more transmissible P.1 variant first identified in Brazil, which is believed to be playing a role in a current surge in cases across South America.
Also there is an opinion that:
"The country may have been too optimistic after their vaccine rollout and opened up too quickly, especially to internal travel during the summer holiday season," said Michael Touchton, from the University of Miami’s Observatory for the Containment of Covid-19 in the Americas. Chile reopened its borders in November 2020 when infections had dropped from its June peak to around 1400 cases a day. It also permitted domestic travel during the country’s December to February holiday season this year, when restaurants, shops, and holiday resorts reopened.
Careless behaviour during the vacations likely facilitated the virus’s spread, experts said.
"At the beginning of the vaccine campaign there was a message from government that ‘vaccines are on their way so the pandemic will end soon.’ Everyone stopped taking care, stopped wearing masks, and joined big crowds during the holiday season," said Claudia Cortés, an infectious diseases specialist at the University of Chile.
Quotes from the link above. Reasons appear to be as you'd expect - although I wasn't aware that the Sinovac vaccine had such low efficacy after single dose. As a second point of reference, CNN has
an article with similar conclusions.
