Saudi Press

Saudi Arabia and the world
Sunday, Jun 01, 2025

AstraZeneca Covid Vaccine Protection Wanes After 3 Months: Lancet Study

AstraZeneca Covid Vaccine Protection Wanes After 3 Months: Lancet Study

The findings drawn from datasets in Brazil and Scotland suggest that booster programmes are needed to help maintain protection from severe disease in those vaccinated with AstraZeneca, known as Covishield in India.
The protection offered by the Oxford-Astra Zeneca COVID-19 vaccine declines after three months of receiving two doses of the preventive, according to a study published in The Lancet journal.

The findings drawn from datasets in Brazil and Scotland suggest that booster programmes are needed to help maintain protection from severe disease in those vaccinated with AstraZeneca, known as Covishield in India.

The researchers analysed data for two million people in Scotland and 42 million people in Brazil who had been vaccinated with the AstraZeneca vaccine.

In Scotland, when compared with two weeks after receiving a second dose, there was approximately a five-fold increase in the chance of being hospitalised or dying from COVID-19 nearly five months after being double vaccinated, the researchers said.

The decline in effectiveness begins to first appear at around three months, when the risk of hospitalisation and death is double that of two weeks after the second dose, they said.

The researchers from Scotland and Brazil found that the risk of hospitalisation and death increases threefold just short of four months after the second vaccine dose. Similar numbers were seen for Brazil, they said.

"Vaccines have been a key tool in fighting the pandemic, but waning in their effectiveness has been a concern for a while," said Professor Aziz Sheikh, from the University of Edinburgh, UK.

"By identifying when waning first starts to occur in the Oxford-AstraZeneca vaccine, it should be possible for governments to design booster programmes that can ensure maximum protection is maintained," Sheikh said.

The team was able to compare data between Scotland and Brazil as they had a similar interval between doses - 12 weeks - and initial prioritisation of who was vaccinated - people at highest risk of severe disease and healthcare workers.

The dominant variant was different in each country during the study period -- Delta in Scotland and Gamma in Brazil.

This means the decline in effectiveness is likely because of vaccine waning and the impact of variants, according to the researchers.

The study also estimated vaccine effectiveness at similar fortnightly intervals by comparing outcomes of people who have been jabbed with those who are not vaccinated.

However, the experts warned that these figures should be treated with caution because it is becoming harder to compare non-vaccinated people to those vaccinated with similar characteristics, particularly among older age groups where so many people are now vaccinated.

"Our analyses of national datasets from both Scotland and Brazil suggest that there is considerable waning of effectiveness for the Oxford AstraZeneca vaccine, with protection against severe COVID-19 falling over time," said Professor Srinivasa Vittal Katikireddi from the University of Glasgow in the UK.

"Our work highlights the importance of getting boosters, even if you've had two doses of the Oxford AstraZeneca vaccine, as soon as you are able to," Srinivasa Katikiredd added.
Newsletter

Related Articles

Saudi Press
0:00
0:00
Close
OPEC+ Agrees to Increase Oil Output for Third Consecutive Month
Turkey Detains Istanbul Officials Amid Anti-Corruption Crackdown
Meta and Anduril Collaborate on AI-Driven Military Augmented Reality Systems
EU Central Bank Pushes to Replace US Dollar with Euro as World’s Main Currency
European and Arab Ministers Convene in Madrid to Address Gaza Conflict
U.S. Health Secretary Ends Select COVID-19 Vaccine Recommendations
Trump Warns Putin Is 'Playing with Fire' Amid Escalating Ukraine Conflict
India and Pakistan Engage Trump-Linked Lobbyists to Influence U.S. Policy
U.S. Halts New Student Visa Interviews Amid Enhanced Security Measures
Trump Administration Cancels $100 Million in Federal Contracts with Harvard
SpaceX Starship Test Flight Ends in Failure, Mars Mission Timeline Uncertain
King Charles Affirms Canadian Sovereignty Amid U.S. Statehood Pressure
Iranian Revolutionary Guard Founder Warns Against Trusting Regime in Nuclear Talks
UAE Offers Free ChatGPT Plus Subscriptions to Citizens
Lebanon Initiates Plan to Disarm Palestinian Factions
Iran and U.S. Make Limited Progress in Nuclear Talks
The Daily Debate: The Fall of the Dollar — Strategic Reset or Economic Self-Destruction?
Trump Administration's Tariff Policies and Dollar Strategy Spark Global Economic Debate
OpenAI Acquires Jony Ive’s Startup for $6.5 Billion to Build a Revolutionary “Third Core Device”
Turkey Weighs Citizens in Public as Erdoğan Launches National Slimming Campaign
Saudi-Spanish Business Forum Commences in Riyadh
Saudi Arabia and Spain Sign MoU to Boost SME Sectors
UK Suspends Trade Talks with Israel Amid Gaza Offensive
Iran and U.S. Set for Fifth Round of Nuclear Talks Amid Rising Tensions
Russia Expands Military Presence Near Finland Amid Rising Tensions
Indian Scholar Arrested in Crackdown Over Pakistan Conflict Commentary
Israel Eases Gaza Blockade Amid Internal Dispute Over Military Strategy
President Biden’s announcement of advanced prostate cancer sparked public sympathy—but behind closed doors, Democrats are in panic
A Chinese company made solar tiles that look way nicer than regular panels!
Indian jet shootdown: the all-robot legion behind China’s PL-15E missiles
The Chinese Dragon: The True Winner in the India-Pakistan Clash
Australia's Venomous Creatures Contribute to Life-Saving Antivenom Programme
The Spanish Were Right: Long Working Hours Harm Brain Function
Did Former FBI Director Call for Violence Against Trump? Instagram Post Sparks Uproar
US and UAE Partner to Develop Massive AI Data Center Complex
Apple's $95 Million Siri Settlement: Eligible Users Have Until July 2 to File Claims
US and UAE Reach Preliminary Agreement on Nvidia AI Chip Imports
President Trump and Elon Musk Welcomed by Emir of Qatar Sheikh Tamim with Cybertruck Convoy
Strong Warning Issued: Do Not Use General Chatbots for Medical, Legal, or Educational Guidance
Saudi Arabia Emerges as Global Tech Magnet with U.S. Backing and Trump’s Visit
This was President's departure from Saudi Arabia. The Crown Prince personally escorted him back to the airport.
NVIDIA and Saudi Arabia Launch Strategic Partnership to Establish AI Centers
Trump Meets Syrian President Ahmad al-Shara in Historic Encounter
Trump takes a blow torch to the neocons and interventionists while speaking to the Saudis
US and Saudi Arabia Sign Landmark Agreements Across Multiple Sectors
Why Saudi Arabia Rolled Out a Purple Carpet for Donald Trump Instead of Red
Elon Musk Joins Trump Meeting in Saudi Arabia
Trump says it would be 'stupid' not to accept gift of Qatari plane
Quantum Computing Threatens Bitcoin Security
Michael Jordan to Serve as Analyst for NBA Games
×