A dad-of-four died of coronavirus a month after getting his first dose of the vaccine.
Chris Moore, 48, had been shielding during the pandemic, but returned to his role as an NHS administrator at the end of last year.
He was given the first dose of the Pfizer jab on January 2 at the University Hospital of North Durham.
But the Shotley Bridge dad began to show symptoms two days later and was subsequently diagnosed with the virus, reports Chronicle Live.
His family are not sure where or how he contracted the virus.
Public health experts have warned the public that a first dose of any coronavirus vaccine doesn’t immediately ensure full immunity.
Studies have found the protective effects kick in around three to four weeks after the Pfizer jab, which is administered in two doses.
Rates of hospitalisation and death from Covid-19 are reduced by 75% from a single dose of the jab, according to Public Health England (PHE).
The results study which monitored vaccinated healthcare workers under 65, was unveiled to the public earlier this week.
It showed one dose reduced the risk of infection by more than 70%, rising to 85% after the second dose.
PHE’s analysis of routine testing data also showed that one dose of the Pfizer jab was 57% effective against symptomatic Covid-19 infection in over-80s from about three to four weeks after the first dose.
This rose to about 30% after a second dose, resulting in more protection against symptomatic cases to more than 85% for over 80s.
Read more: Tributes paid to dad who died from ‘Covid’ despite ‘shielding for most of pandemic’