International Desk:
Dhaka, Oct-05,
Vaccination with two doses of the Pfizer jab stays highly effective against severe Covid -- including the Delta variant -- for at least six months, an analysis of US patients said Monday.
While previous data
from clinical trials has shown jabs protect against hospitalisation, the study
published in the Lancet measures one vaccine's effectiveness over time in a
real-world setting.
Pfizer and healthcare
provider Kaiser Permanente looked at records from 3.4 million residents of
southern California, about a third of who were fully vaccinated between
December 2020 and August 2021.
After an average period
of three to four months, fully vaccinated people were found to be 73 percent
protected against infection and 90 percent protected against hospitalisation.
But while protection
against infection from Delta fell by 40 percent over five months, protection
against hospitalisation involving cases from all variants remained very high
for the duration of the study.
The results, the study
notes, are consistent with preliminary data from US and Israeli health
authorities.
Reduced infection
defence is "likely to be primarily due to waning vaccine effectiveness
rather than the delta variant escaping vaccine protection", the authors
conclude.
"Our findings
underscore the importance of monitoring vaccine effectiveness over time and
suggest that booster doses are likely to be needed to restore the initial high
amounts of protection observed early in the vaccination programme," it
says.
In August the US
authorised an extra dose of Covid-19 vaccine for people with weakened immune
systems, while in France an extra shot has been offered to the elderly.
Israel has gone
further, offering children 12 and older a third dose five months after
receiving a second jab.
A September report,
however, from the World Health Organization (WHO) found current vaccines are
effective enough against severe Covid to make a third jab unnecessary for the
general population.
The WHO last month
called for a moratorium on booster jabs until the end of the year to address
the drastic inequity in dose distribution between rich and poor nations.
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