Please login to the form below

Not currently logged in
Email:
Password:

Study finds mixed vaccine schedules provide strong immune response against COVID-19

And AZ's Vaxzevria COVID-19 vaccine shows strong immune responses following a delayed second dose

Mixing COVID-19 vaccines as part of a two-dose schedule generates a strong immune response against the SARS-CoV-2 virus, a study led by Oxford University suggests.

The Com-Cov study was initially launched in February, becoming the first trial in the world to evaluate whether different vaccines can be used safely and effectively as part of two-dose regimens.

The first results from the study suggest that two mixed schedules – a first dose of the Pfizer/BioNTech vaccine followed by the AstraZeneca/Oxford University vaccine or a first dose of the AstraZeneca/Oxford University vaccine followed by the Pfizer/BioNTech vaccine – provide good protection against COVID-19.

Specifically, these mixed vaccine schedules induced high concentrations of antibodies against the SARS-CoV-2 spike IgG protein when the doses were given four weeks apart.

However, the researchers did note some differences between the vaccine regimens, with certain schedules inducing higher antibodies and T-cell responses compared to others.

Notably, administering a first dose of the AZ/Oxford vaccine followed by the Pfizer/BioNTech vaccine induced both higher antibody levels and T-cell responses compared to Pfizer/BioNTech followed by AZ/Oxford.

Both of these mixed regimens induced higher antibodies than the standard two-dose AZ/Oxford vaccine schedule, while the highest antibody response was observed following the standard two-dose Pfizer/BioNTech schedule.

Researchers also discovered that the AZ/Oxford vaccine followed by the Pfizer/BioNTech vaccine induced the highest T-cell responses.

“Today’s data [is] a vital step forward, showing a mixed schedule gives people protective immunity against COVID-19 after four weeks. Equally, they offer supportive evidence that the standard (non-mixed) JCVI recommendations for COVID-19 vaccination all produce highly satisfactory immune responses, for both main vaccines in use,” said Jonathan Van-Tam, deputy chief medical officer.

“Given the UK’s stable supply position there is no reason to change vaccine schedules at this moment in time. The results for the 12-week interval, which are yet to come, will have an instrumental role to play in decisions on the future of the UK’s vaccination programme,” he added.

AZ reveals new data for its Vaxzevria COVID-19 vaccine

AZ has also revealed new data from a sub-analysis of two Oxford University-led trials, showing that its vaccine – marketed as Vaxzevria in the EU – induced strong immune responses following a delayed second dose interval of up to 45 weeks or after a third booster dose.

When the interval between the first and second dose of the vaccine was extended by up to 45 weeks, antibody responses increased 18-fold, as measured 28 days after the second dose.

In addition, with a 45-week dosing interval between the first and second doses of the vaccine, antibody titres were four times higher than with a 12-week interval.

The researchers also found that a third dose of Vaxzevria, administered at least six months after the second dose, increased antibody levels six-fold and also induced higher neutralising activity against the Alpha, Beta and Delta variants.

Article by
Lucy Parsons

29th June 2021

From: Research

Share

Tags

COVID-19 Updates and Daily News

Featured jobs

PMHub

Add my company
Blue Latitude Health

Blue Latitude Health is a creative marketing consultancy. Founded in 2003, our combination of heritage, approach and capability gives us...

Latest intelligence

Menopause-thumbnail.png
Breaking the silence: It’s time to talk about the menopause
Using findings from our latest opinion poll, Vicki Newlove outlines why the hidden landscape of menopause may finally be starting to change....
Committing time to making meaningful connections - top 5 tips
Read the second blog of the series looking at key barriers to effective patient engagement in pharma...
News:
Senior Analytics Specialist joins Research Partnership...