AstraZeneca Booster As Effective Against Omicron As mRNA Vaccines

A newly published review shows that any three-dose schedule including the AstraZeneca vaccine is 84.8%-89.2% effective against severe Omicron disease.

KUALA LUMPUR, Sept 13 — Boosting with AstraZeneca’s vaccine and mRNA Covid-19 vaccines provide equally high protection against Omicron-related severe outcomes, including hospitalisation and death, even as new subvariants of the virus emerge, according to an expert review of more than 50 real-world studies.

The newly published review demonstrates that any three-dose schedule, including the AstraZeneca vaccine, was highly effective at protecting against severe Omicron outcomes (84.8 per cent to 89.2 per cent). Three dose schedules including mRNA vaccines showed equivalent effectiveness.

The review authors conclude that the administration of a fourth dose booster is likely to add a significant level of additional protection, with a recent real-world study from Asia, demonstrating no cases of severe outcomes due to Omicron in people vaccinated with a fourth dose of either the AstraZeneca vaccine or a mRNA Covid-19 vaccine during the February to April 2022 analysis period.

Prof Suwat Chariyalertsak, Dean of the Faculty of Public Health at Chiang Mai University in Thailand, and one of the review’s authors, said: “With Omicron infections dominant globally, it is vital to understand how the most widely used vaccines protect people against the most contagious Covid-19 variant yet.

“This expert analysis tells us that the most effective way to continue saving lives from severe Omicron-related outcomes is the expansion of booster coverage using already available vaccines.”

The 22 independent international infectious disease experts from across Asia and Latin America involved in the review concluded that a sustainable annual boosting strategy could include once a year boosting for the general population, and every six months for vulnerable groups, such as those living with chronic conditions.

Prof Guy Thwaites, director of the Oxford Clinical Research Unit in Vietnam and one of the study’s authors said: “Booster dose data is critical for informing ongoing vaccination strategies as we transition from pandemic to endemic, whether that is an annual vaccine for most people, or every six months for those considered to be more vulnerable.

“This expert review of data can reassure governments and the public that viral vector and mRNA Covid-19 vaccines offer great booster protection against serious outcomes in the ongoing battle against Omicron, particularly because that protection also shows very little
sign of waning, even after a three-month period.”

The review, published online last September 7, analysed more than 50 global real-world studies hosted on ViewHub, a robust, interactive platform for visualising global data on vaccine use and impact, developed by Johns Hopkins Bloomberg School of Public Health and the International Vaccine Access Center.

The reviewed data also showed that other vaccines used as boosters perform well against Omicron but appear slightly less effective than AstraZeneca’s vaccine and the mRNA Covid-19 vaccines.

AstraZeneca’s vaccine is a ‘viral vector’ vaccine, which means a version of a virus that cannot cause disease is used as part of the vaccine, so if the body is exposed to the real virus later it is able to fight it.

This vaccine technology has been used by scientists over the past 40 years to fight other infectious diseases such as the flu, Zika, Ebola and HIV.

AstraZeneca and its global partners have released over three billion vaccine doses to more than 180 countries, and approximately two-thirds of these doses have been delivered to low- and lower-middle-income countries.

The vaccine is estimated to have helped save over six million lives during the first 12 months of use since December 2020, according to data from leading health analytics firm Airfinity.

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