US study indicates drop in Pfizer jab effectiveness, after 6 months.
An immunology professor says data from studies on vaccines shows more people will need boosters than are currently receiving them.
One such research project from the United States found that the Pfizer jab's effectiveness against infection falls significantly over 6 months.
While another from Public Health England study compared Pfizer with Moderna and AstraZeneca's jabs
Trinity College Dublin Professor, Kingston Mills, says one of the three stood out