Novavax gives us first vaccine efficacy data we’ve seen against B117 (UK) and B1351 (South Africa) variants, from trial results just reported.

In UK the news is good: 89% efficacy in preventing symptomatic disease overall in 15k-person phase 3 trial (1)
Novavax reports more than half of cases in the UK trial were B117 variant. When they looked back at efficacy against B117 vs prior strains they found:

Prior strains: 95.6% efficacy
B117 variant: 85.6% efficacy (2)

The news isn’t quite so good against B.1.351 (2)
Novavax reports results from ph2b trial in South Africa. 4400 participants, 94% who were HIV-negative.

90% of cases in trial were B.1.351.

Efficacy: 60% for people who were HIV-negative.

For everyone, efficacy: 49%.

There’s more (3)
Novavax: data on prior infection in people in trial (but not included in primary analyses) “suggest that prior infection with #covid19 may not protect against subsequent infection by the South Africa escape variant; however, vaccination... provided significant protection.” (4)
Novavax says it started development of new constructs against emerging strains in early January, expects to select candidates for booster of combination bivalve to vaccine in coming days. Plans to start clinical testing of new vaccines in Q2. (5)
Next up: results on J&J’s vaccine, whose trials were also run in South Africa as well as Brazil (and U.S., among other countries). Expected within days.

Note: we don’t have efficacy data from real world on how well Pfizer & Moderna vaccines work against variants, just lab work.
Should also note Novavax results were an interim analysis from UK (62 total cases: 56 on placebo including 1 severe, 6 on vaccine none severe).

South Africa trial also small numbers as a phase 2B: 29 cases on placebo, 1 severe; 15 on vaccine none severe.
Interestingly, $NVAX stock up 23% (after originally being down 8% on the headlines)

$MRNA +2.6%
Novavax slide on prevalence of B117 variant in its UK #covid19 vaccine trial
Novavax case breakdown in interim analysis of UK #covid19 vaccine trial
Novavax breakdown by variant in UK #covid19 vaccine trial:
Novavax safety slide for UK #covid19 vaccine trial:
Novavax slides on South Africa #covid19 vaccine trial
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