There are strict protections in place to help ensure the safety of all COVID-19 vaccines. Before receiving validation from WHO and national regulatory agencies, COVID-19 vaccines must undergo rigorous testing in clinical trials to prove that they meet internationally agreed benchmarks for safety and effectiveness.

More serious or long-lasting side effects to vaccines are possible but extremely rare. Vaccines are continually monitored to detect rare adverse events. Reported side effects to COVID-19 vaccines have mostly been mild to moderate and short-lasting. They include: fever, fatigue, headache, muscle pain, chills, diarrhoea, and pain at the injection site. The chances of any of these side effects following vaccination differ according to the specific COVID-19 vaccine.

While several COVID-19 vaccines appear to have high levels of efficacy, no vaccine is 100% protective. In addition to a vaccine's specific characteristics, several factors such as a person's age, their underlying health conditions or previous exposure to COVID-19 may have an impact on a vaccine’s effectiveness. We also do not yet know how long immunity from different COVID-19 vaccines will last. That is one reason why, even as COVID-19 vaccines start to be rolled out, we must continue using all public health measures that work, such as physical distancing, masks, and handwashing.

Based on what we know about these vaccines, we don’t have any specific reason to believe there will be risks that would outweigh the benefits of vaccination for pregnant women. While pregnancy puts women at higher risk of severe COVID-19, very little data are available to assess vaccine safety in pregnancy.

For this reason, those pregnant women at high risk of exposure to SARS-CoV-2 (e.g., health workers) or who have comorbidities which add to their risk of severe disease may be vaccinated in consultation with their health care provider.

Vaccine safety monitoring is ensured at the national, regional, and global level. As is standard practice in all national immunization programmes, WHO supports the set up of safety monitoring systems for COVID-19 vaccines in every country. After a COVID-19 vaccine is introduced in a country, WHO works with vaccine manufacturers, health officials and other partners to track safety concerns and potential side effects on an ongoing basis. Specific safety concerns that may arise will be evaluated by WHO and an independent group of experts (the Global Advisory Committee on Vaccine Safety, or GACVS) in conjunction with the relevant national authorities.