The World Health Organization (WHO) has authorized several COVID-19 vaccines through its Emergency Use Listing process, which helps countries worldwide decide which vaccines meet international standards for safety and effectiveness. As of 2025, the WHO also guides how those vaccines are updated to match circulating variants and who should be prioritized for doses. Here’s what you need to know about the current state of WHO-backed COVID vaccination.
How the WHO Approves COVID Vaccines
The WHO uses a process called Emergency Use Listing (EUL) to evaluate COVID-19 vaccines. This isn’t the same as approval by a national regulator like the FDA. Instead, it’s a global benchmark that signals to lower-income countries, procurement agencies like UNICEF, and international aid programs that a vaccine meets minimum standards for quality, safety, and effectiveness. Vaccines that earn this listing can be distributed through programs like COVAX.
The most recent addition to the WHO’s EUL is Corbevax, a protein subunit vaccine made by Biological E. Limited in India. Protein subunit vaccines use a small, harmless piece of the virus to train the immune system, rather than mRNA or a viral vector. Several other vaccine types, including mRNA (Pfizer-BioNTech, Moderna), viral vector (AstraZeneca, Johnson & Johnson), and inactivated virus platforms, have previously received WHO emergency authorization.
Current Vaccine Composition Recommendations
The WHO maintains a Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) that periodically recommends which viral strains vaccines should target. As of May 2025, the group advises that monovalent vaccines based on the JN.1 or KP.2 lineages remain appropriate. A newer lineage called LP.8.1 is also considered a suitable alternative target.
This matters because the virus continues to evolve. Earlier vaccines targeted older variants that no longer circulate widely. Data from the New England Journal of Medicine showed that vaccines targeting the XBB.1.5 subvariant peaked at about 52% effectiveness against infection four weeks after vaccination, then dropped to roughly 20% by 20 weeks. Protection against hospitalization held up better, starting at nearly 67% and staying around 57% at 10 weeks. Crucially, those vaccines were less effective against the JN.1 lineage than against the XBB sublineages they were designed for, which is exactly why the WHO keeps updating its composition recommendations.
Who Should Get Vaccinated Now
COVID-19 vaccination recommendations have shifted from universal campaigns to a more individualized approach. In the United States, updated guidance applies to everyone aged 6 months and older but emphasizes shared decision-making between patients and healthcare providers, weighing personal risk factors against the benefits of vaccination.
Certain groups are still strongly encouraged to stay up to date:
- Adults 65 and older are recommended to receive a second dose of the current season’s vaccine, spaced about 6 months after their first dose (though it can be given as early as 2 months later).
- People with moderate or severe immune compromise of any age (starting at 6 months) are also recommended at least two doses of the current vaccine, with the option for additional doses based on their clinical situation.
- Pregnant women are considered at higher risk for severe COVID illness. Studies involving more than a million pregnant women worldwide have found no increased risk of miscarriage, preterm delivery, stillbirth, or birth defects from vaccination. Vaccination is considered safe at any point during pregnancy.
- Breastfeeding women can also be vaccinated. No evidence of harm to the mother or breastfed infant has been identified.
For young children aged 6 months through 4 years, the only currently available vaccine in the U.S. is Moderna’s Spikevax. Pfizer-BioNTech is no longer authorized for that age group.
Known Side Effects and Safety Signals
The most common side effects remain mild: injection-site pain (reported by about 53% of recipients) and headache (about 9%), both typically appearing within a day of the dose and resolving quickly.
The WHO’s Global Advisory Committee on Vaccine Safety identified a few rare but serious signals over the course of the pandemic. For mRNA vaccines (Pfizer-BioNTech and Moderna), the primary concerns have been myocarditis and pericarditis, which are forms of heart inflammation, most frequently observed in adults aged 18 to 35. Anaphylaxis, a severe allergic reaction, has also been documented but remains very uncommon. For adenovirus vector vaccines (like the AstraZeneca and Johnson & Johnson shots), a rare blood-clotting condition called thrombosis with thrombocytopenia syndrome was identified early on and led to clinical guidance on diagnosis and treatment.
The WHO’s formal safety subcommittee has since been disbanded, but ongoing monitoring continues for the long-term effects of vaccine-related myocarditis, pregnancy outcomes, and Guillain-Barré syndrome (a rare nerve disorder linked to viral vector vaccines). Safety of newly formulated vaccines is also tracked as they roll out.
Global Vaccination Coverage
Globally, about 71% of people have completed a primary vaccination series (typically two doses). Booster uptake tells a different story: only about 37% of the world’s population has received at least one booster dose. That gap reflects a combination of vaccine fatigue, supply challenges in lower-income countries, and shifting public health priorities as the pandemic phase has wound down.
The WHO’s Emergency Use Listing process was designed partly to close this gap by making it easier for countries without their own rigorous regulatory agencies to access vetted vaccines. Whether that translates into higher booster coverage going forward depends largely on national health policies and individual willingness to get updated doses as new formulations become available.