|
 "We found a really good immune response across the board..., in
fact, higher than the threshold set by Oxford-AstraZeneca vaccine
two doses," Matthew Snape, the Oxford professor behind the trial
dubbed Com-COV2, told Reuters.
The findings supporting flexible dosing will offer some hope to poor
and middle income countries which may need to combine different
brands between first and second shots if supplies run low or become
unstable.
"I think the data from this study will be especially interesting and
valuable to low- and middle-income countries where they're still
rolling out the first two doses of vaccines," Snape said.
"We're showing...you don't have to stick rigidly to receiving the
same vaccine for a second dose...and that if the programme will be
delivered more quickly by using multiple vaccines, then it is okay
to do so."
If the AstraZeneca-Oxford vaccine is followed by a Moderna or
Novavax shot, higher antibodies and T-cell responses were induced
versus two doses of AstraZeneca-Oxford, according to researchers at
the University of Oxford.
The study of 1,070 volunteers also found that a dose of the Pfizer-BioNTech
vaccine followed by a Moderna shot was better than two doses of the
standard Pfizer-BioNTech course.
Pfizer-BioNTech followed by Novavax induced higher antibodies than
the two-dose Oxford-AstraZeneca schedule, although this schedule
induced lower antibody and T-cell responses than the two-dose
Pfizer-BioNTech schedule.
No safety concerns were raised, according to the Oxford University
study published in the Lancet medical journal.
Many countries have been deploying a mix and match well before
robust data was available as nations were faced with soaring
infection numbers, low supplies and slow immunisation over some
safety concerns.
"
[to top of second column] |
 Longevity of protection offered
by vaccines has been under scrutiny, with
booster doses being considered as well amid
surging cases. New variants, including Delta and
Omicron, have now increased the pressure to
speed up vaccination campaigns.
Blood samples from participants were tested
against the Wild-Type, Beta and Delta variants,
researchers of the Com-COV2 study said, adding
that vaccines' efficacy against the variants had
waned, but this was consistent across mixed
courses.
Deploying vaccines using technology from
different platforms - like Pfizer and Moderna's
mRNA, AstraZeneca's viral vector and Novavax's
protein-based shot - and within the same
schedule is new.
The results may inform new approaches to
immunisation against other diseases, he said.
The study also found that a first dose of the
AstraZeneca-Oxford vaccine followed by any of
the other candidates in the study generated a
particularly robust response, consistent with
findings in June.
The study was designed as a so-called
"non-inferiority" study – the intent is to
demonstrate that mixing is not substantially
worse than the standard schedules - and compares
the immune system responses to the gold-standard
responses reported in previous clinical trials
of each vaccine.
(Reporting by Pushkala Aripaka in Bengaluru;
Editing by Josephine Mason and Mark Heinrich)
[© 2021 Thomson Reuters. All rights
reserved.] Copyright 2021 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
Thompson Reuters is solely responsible for this content
 |
