^^^ the Brazilian government has already placed an order for about 30 million doses of the AstraZeneca - Oxford vaccine for December and January, pending a positive result in the phase III trials. It does seem indeed to be the most advanced one.
OT -
Some more good news on the prospect of T-cell mediated immunity:
https://www.researchsquare.com/article/rs-35331/v1
https://www.biorxiv.org/content/10.1101/2020.06.29.174888v1
The studies suggest not only there are more people with T-cell mediated response to SARS-CoV-2 than there are with antibodies (meaning a lower IFR), but also reinforce previous research concerning cross-reactivity with the response generated to the other human coronaviruses, present in about 80% of people. This was correlated to a milder course of disease, as opposed to an ADE mechanism making it more severe, as some had feared.
It could also explain why precisely some 80% of people seem to be asymptomatic or minimally symptomatic and children immunity as well, since they contract 6 - 12 colds every year, and thus have very strong learned immune responses at all times.
On the other hand, complete immunity to human coronaviruses seem to last for just about a year, on average:
https://www.medrxiv.org/content/10.1101/2020.05.11.20086439v2.full.pdf
Although the previous studies concerning T-cells might be of some consolation, since these last far longer than plasmocyte antibodies and will lead to milder or asymptomatic reinfections as long as they are present.
