Saudi Press

Saudi Arabia and the world
Friday, Aug 22, 2025

Pfizer, Moderna Vaccines Highly Effective Even After 1st Shot: US Study

Pfizer, Moderna Vaccines Highly Effective Even After 1st Shot: US Study

The risk of infection fell 90 per cent by two weeks after the second shot, the study of just under 4,000 people found.
COVID-19 vaccines developed by Pfizer Inc with BioNTech SE and Moderna Inc reduced the risk of infection by 80 per cent two weeks or more after the first of two shots, according to data from a real-world study of vaccinated US healthcare personnel and first responders released on Monday.

The risk of infection fell 90 per cent by two weeks after the second shot, the study of just under 4,000 people found.

The study by the US Centers for Disease Control and Prevention (CDC) evaluated the vaccines' ability to protect against infection, including infections that did not cause symptoms. Previous clinical trials by the companies evaluated their vaccine's efficacy in preventing illness from COVID-19.

"This study shows that our national vaccination efforts are working," CDC Director Rochelle Walensky said in a statement.

The findings from of the real-world use of these messenger RNA (mRNA) vaccines confirm what was seen in large controlled clinical trials conducted before they received emergency use authorizations from the U.S. Food and Drug Administration.

The study looked at the effectiveness of the mRNA vaccines among 3,950 participants in six states over a 13-week period from Dec. 14, 2020 to March 13, 2021.

"The authorized mRNA COVID-19 vaccines provided early, substantial real-world protection against infection for our nation's healthcare personnel, first responders, and other frontline essential workers," Walensky said.

The new mRNA technology is a synthetic form of a natural chemical messenger being used to instruct cells to make proteins that mirror part of the novel coronavirus. That teaches the immune system to recognize and attack the actual virus.
Newsletter

Related Articles

Saudi Press
0:00
0:00
Close
Dogfights in the Skies: Airbus on Track to Overtake Boeing and Claim Aviation Supremacy
Tim Cook Promises an AI Revolution at Apple: "One of the Most Significant Technologies of Our Generation"
Are AI Data Centres the Infrastructure of the Future or the Next Crisis?
Miles Worth Billions: How Airlines Generate Huge Profits
Zelenskyy Returns to White House Flanked by European Allies as Trump Pressures Land-Swap Deal with Putin
Beijing is moving into gold and other assets, diversifying away from the dollar
Cristiano Ronaldo Makes Surprise Stop at New Hong Kong Museum
Zelenskyy to Visit Washington after Trump–Putin Summit Yields No Agreement
High-Stakes Trump-Putin Summit on Ukraine Underway in Alaska
Iranian Protection Offers Chinese Vehicle Shipments a Cost Advantage over Japanese and Korean Makers
Saudi Arabia accelerates renewables to curb domestic oil use
Cristiano Ronaldo and Georgina Rodríguez announce engagement
Asia-Pacific dominates world’s busiest flight routes, with South Korea’s Jeju–Seoul corridor leading global rankings
Private Welsh island with 19th-century fort listed for sale at over £3 million
Sam Altman challenges Elon Musk with plans for Neuralink rival
Australia to Recognize the State of Palestine at UN Assembly
The Collapse of the Programmer Dream: AI Experts Now the Real High-Earners
Armenia and Azerbaijan to Sign US-Brokered Framework Agreement for Nakhchivan Corridor
British Labour Government Utilizes Counter-Terrorism Tools for Social Media Monitoring Against Legitimate Critics
WhatsApp Deletes 6.8 Million Scam Accounts Amid Rising Global Fraud
Nine people have been hospitalized and dozens of salmonella cases have been reported after an outbreak of infections linked to certain brands of pistachios and pistachio-containing products, according to the Public Health Agency of Canada
Texas Residents Face Water Restrictions While AI Data Centers Consume Millions of Gallons
Tariffs, AI, and the Shifting U.S. Macro Landscape: Navigating a New Economic Regime
India Rejects U.S. Tariff Threat, Defends Russian Oil Purchases
United States Establishes Strategic Bitcoin Reserve and Digital Asset Stockpile
Thousands of Private ChatGPT Conversations Accidentally Indexed by Google
China Tightens Mineral Controls, Curtailing Critical Inputs for Western Defence Contractors
OpenAI’s Bold Bet: Teaching AI to Think, Not Just Chat
BP’s Largest Oil and Gas Find in 25 Years Uncovered Offshore Brazil
JPMorgan and Coinbase Unveil Partnership to Let Chase Cardholders Buy Crypto Directly
British Tourist Dies Following Hair Transplant in Turkey, Police Investigate
WhatsApp Users Targeted in New Scam Involving Account Takeovers
Trump Deploys Nuclear Submarines After Threats from Former Russian President Medvedev
Germany’s Economic Breakdown and the Return of Militarization: From Industrial Collapse to a New Offensive Strategy
IMF Upgrades Global Growth Forecast as Weaker Dollar Supports Outlook
Politics is a good business: Barack Obama’s Reported Net Worth Growth, 1990–2025
"Crazy Thing": OpenAI's Sam Altman Warns Of AI Voice Fraud Crisis In Banking
Japanese Prime Minister Vows to Stay After Coalition Loses Upper House Majority
President Trump Diagnosed with Chronic Venous Insufficiency After Leg Swelling
Man Dies After Being Pulled Into MRI Machine Due to Metal Chain in New York Clinic
FIFA Pressured to Rethink World Cup Calendar Due to Climate Change
"Can You Hit Moscow?" Trump Asked Zelensky To Make Putin "Feel The Pain"
Nvidia Becomes World’s First Four‑Trillion‑Dollar Company Amid AI Boom
Iranian President Reportedly Injured During Israeli Strike on Secret Facility
Kurdistan Workers Party Takes Symbolic Step Towards Peace in Northern Iraq
BRICS Expands Membership with Indonesia and Ten New Partner Countries
Elon Musk Founds a Party Following a Poll on X: "You Wanted It – You Got It!"
AI Raises Alarms Over Long-Term Job Security
Saudi Arabia Maintains Ties with Iran Despite Israel Conflict
Russia Formally Recognizes Taliban Government in Afghanistan
×