London: The protection gained after being fully vaccinated with both doses of the Pfizer/BioNTech and Oxford/AstraZeneca vaccines against Covid-19 decreases over time, a new study in the United Kingdom (UK) reported Wednesday.
The ZOE COVID Study found that protection after two shots of the Pfizer/BioNTech vaccine decreased from 88 per cent at one month to 74 per cent at five to six months. In case of AstraZeneca the protection dipped to 67 per cent in the same time frame from 77 per cent. Incidentally, the Oxford vaccine is being administered in India as Covishield.
The findings would seem to reaffirm the UK government’s plan to offer booster shots to the most vulnerable groups, expected from next month.
“In my opinion, a reasonable worst-case scenario could see protection below 50 per cent for the elderly and healthcare workers by winter,” said Professor Tim Spector, lead scientist on the study. However, he insisted that vaccines still provide strong protection against severe Covid-19, especially against the highly transmissible Delta variant.
“Waning protection is expected and is not a reason to avoid vaccination. Vaccines still provide high levels of protection for the majority of population, especially against the Delta variant. Hence we still need as many people as possible to get fully vaccinated,” pointed out Spector.
With such a situation looming, Spector said ‘urgency’ is needed to make plans for ‘vaccine boosters’. The boosters will help in reduction of the death rate and hospital admissions.
The vast study involved more than 1.2 million test results and participants, though the vaccines were not examined against the now dominant Delta variant of the virus.
Meanwhile, the Department of Health and Social Care (DHSC) confirmed a new clinical trial to determine whether a third so-called booster dose of vaccine will improve the immune response for people who have weakened immune systems is launching in the UK.
The study, ‘OCTAVE DUO’, will offer people who are immunosuppressed or immunocompromised a Pfizer, Moderna or Novavax vaccine to determine whether this will give a stronger immune response than just two doses of two-dose vaccines.
“We know some people may get less protection from the vaccine than others, so we are planning for a booster programme in autumn, prioritising those most at risk,” UK Health Secretary Sajid Javid said.