Twitter fact checks user for citing Pfizer data: Twitter fact-checked a user's tweet about Pfizer data. Harris said, "Pfizer data released today. 80,000 pages. Pfizer knew vaccine harmed the fetus in pregnant women, and that the vaccine was not 95% effective, Pfizer data shows it having a 12% efficacy rate." Twitter claimed the tweet was "misleading" and linked to an article where readers could "learn why health officials consider COVID-19 vaccines safe for most people." Fact-checked posts lose exposure and are negatively affected by the platform's algorithm. Twitter also prevented other users from liking, sharing or replying to Harris' tweet.