NEW—Preliminary results from Russian trials find that #COVID19 vaccine candidates led to no serious adverse events and elicit antibody response

Thread (1/8)
The new paper reports the findings of two open-label, non-randomised phase 1/2 trials looking at a frozen formulation and a freeze-dried formulation of a two-part #COVID19 vaccine (2/8)
The two-part #COVID19 vaccine included two adenovirus vectors – recombinant human adenovirus type 26 (rAd26-S) and recombinant human adenovirus type 5 (rAd5-S) (3/8)
In phase 1 of each trial, individual components of the two-part vaccine (rAd26-S & rAd5-S) were tested for safety

Phase 2 tested whether the vaccine elicited an immune response by giving the full two-part vaccine – rAd26-S was given first, then rAd5-S was given 21 d later (4/8)
The two 42-day trials – including 38 healthy adults each – did not find any serious adverse effects among participants (5/8)
The two 42-day trials also confirmed that the vaccine candidates elicit an antibody response (6/8)
Secondary outcomes from the trial also suggest the vaccines also produce a T cell and neutralising antibody response within 28 days (7/8)
Large, long-term trials including a placebo comparison and further monitoring, are needed to establish the long-term safety and effectiveness of the vaccine for preventing #COVID19 infection (8/8)
In a Comment, @naorbz & @T_Inglesby describe the studies as "encouraging but small. The immunogenicity bodes well, although nothing can be inferred on immunogenicity in older age groups & clinical efficacy for any #COVID19 vaccine has not yet been shown"

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