Covid-19 vaccine has been hit by an outbreak of the virus.Experts have warned it showed that the shot was not enough to bring the pandemic to an end on its own.Groups representing families said they knew of other homes where residents had been treated but later developed symptoms.Abercorn Care Home in Hamilton received the Pfizer vaccine on December 14.That vaccine, the first in the UK to be given a safety licence, is most effective after two doses, the pharma firm says.Annie Innes, 90, who