Covid-19: Pfizer vaccine’s efficacy declined from 96% to 84% four months after second dose, company reports

@article{Mahase2021Covid19PV,
  title={Covid-19: Pfizer vaccine’s efficacy declined from 96\% to 84\% four months after second dose, company reports},
  author={Elisabeth Mahase},
  journal={BMJ},
  year={2021},
  volume={374}
}