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Pfizer to start trials for updated Covid-19 vaccine designed to fight delta variant

By | Written by Ayshee Bhaduri | Edited by Avik Roy, Hindustan Times, New Delhi
Jul 28, 2021 06:38 PM IST

Pfizer’s announcement comes against the backdrop of the United States and Israel reporting breakthrough infections in fully vaccinated individuals

American pharmaceutical giant Pfizer announced plans to start immunogenicity and safety study in August to evaluate the updated version of Covid-19 vaccine designed to target the more infectious delta variant. "We also plan to start an immunogenicity and safety study in August to evaluate an updated version of our vaccine specifically designed to target the Delta variant," The US-based pharma company said in a statement.

Pfizer also announced that a third booster dose will most likely be needed to be administered 6 to 12 months after both doses have been given. REUTERS(REUTERS)

Pfizer’s announcement comes against the backdrop of the United States and Israel reporting breakthrough infections in fully vaccinated individuals. In the US, a top health official based in Los Angeles said fully vaccinated people made up one-in-five Covid-19 infections in June and cautioned that the figure has potential to rise in July with a higher level of community transmission. The data came a week after Los Angeles re-imposed the mask mandate for vaccinated individuals.

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Data published by the Israeli health ministry for the period of January 24 to April 3, found the Pfizer-BioNTech SE vaccine to be 97.5% effective against severe disease but this went down to 64% when a similar trial was conducted in vaccinated peoples from June 6 to July 3; and in the latest trial conducted between June 20 and July 17 the vaccine’s efficacy was down to 39%, reported the New York Times.

Israeli officials have however cautioned against reading too much into the latest information as it deals with a very short time span. About 60% of Israel's 9.3 million population have received at least one shot of Pfizer's vaccine, and more than half the total population has received both Pfizer shots. The decline also coincided with the end of social distancing measures in the country and the rapid spread of the delta variant.

Also Read: Joe Biden urges vaccinations as US sees surge in Covid cases

A Pfizer spokesperson however told reporters on June 24 that the vaccine was highly effective against the delta variant. "The data we have today, accumulating from research we are conducting at the lab and including data from those places where the Indian variant, Delta, has replaced the British variant as the common variant, point to our vaccine being very effective, around 90%, in preventing the coronavirus disease, COVID-19," Alon Rappaport, Pfizer's medical director in Israel, told local broadcaster Army Radio.

An analysis by Public Health England (PHE), where the Delta variant is more widespread, found that both the Pfizer/BioNTech and AstraZeneca vaccines provide more than 90% protection against hospitalization from the Delta variant.

Pfizer also announced that a third booster dose will most likely be needed to be administered 6 to 12 months after both doses have been given to maintain highest levels of protection, studies for which are underway. Pfizer is currently seeking emergency authorisation from the US for a third dose of its vaccine

“We continue to believe it is likely that a third dose booster may be needed within 6 to 12 months after full vaccination to maintain the highest levels of protection, and studies are underway to evaluate the safety and immunogenicity of a third dose," it added in its quarterly earnings update today.

US infectious diseases expert Anthony Fauci too had made a similar comment on immunocompromised people needing a third booster dose of the vaccine. Israel is also contemplating administering a booster dose to the country’s vulnerable population before the US approval comes along.

"On the one hand we want to see that it is safe and effective and to rely on our data examining whether there really is waning immunity, and on the other hand there is an outbreak and we want to stop this outbreak," health ministry director-general Nachman Ash said on July 26, reported Reuters.

All India Institute of Medical Sciences (AIIMS) chief Dr Randeep Guleria said vaccine booster doses may be needed to fend off infections as newer variants emerge. "It seems that we probably need the booster dose of vaccines as with the passage of time the immunity tends to fall. There is waning immunity. We would like to have booster doses that will cover for various emerging variants,"

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