Source: United States & Canada – South China Morning PostPeople who got Johnson & Johnson Inc’s Covid-19 vaccine as a first shot had a stronger immune response when boosted with vaccines from Pfizer Inc/BioNTech SE or Moderna Inc, a study run by the National Institutes of Health showed on Wednesday.The study, which is preliminary and has not been peer reviewed, is the latest challenge to J&J’s efforts to use its Covid-19 vaccine as a booster in the United States.The study, which included more than 450 adults who received initial shots from Pfizer,…Read More