The GACVS COVID-19 Subcommittee met virtually on Thursday, 25 February 2021, to review available information and data on reports of influenza-like illness in health-care workers who had received COVID-19 vaccines . These symptoms have been reported in several countries.
The Subcommittee reviewed clinical trial data and a summary of reports of influenza-like illness following vaccination with COVID-19 vaccines in the WHO global Individual Case Safety Reports database (VigiBase).
The Subcommittee noted that similar symptoms of influenza-like illness had also been reported in the first few days following vaccination with COVID-19 vaccines in clinical trials. These included headache, fatigue, muscle aches, feverishness and chills. Most symptoms were mild to moderate and resolved within a few days. These expected side effects from vaccination were more common in younger vaccine recipients (under the age of 55 years) compared with older people.
Based on a careful scientific review of the information made available, the Subcommittee came to the following conclusions:
- Symptoms of an influenza-like illness may be expected as immune responses following vaccinations in general.
- The current reports with the COVID-19 vaccines are consistent with the expected side-effect profile of these vaccines, all of which were well tolerated.
In view of this, the committee considers that the benefit-risk balance of the COVID-19 vaccines (for which reports of the influenza-like reactions are available to date) remains favourable and does not suggest any revision, at present, to the recommendations around the safety of these vaccines.
The committee recommends that people who are vaccinated be informed, prior to vaccination, of the potential for influenza-like symptoms to occur after receipt of COVID-19 vaccines. Such symptoms should be managed accordingly, with medical advice sought if required. The occurrence of transient symptoms such as headache, fever and muscle aches after a first dose of these vaccines should not prevent administration of the second dose.
The potential for short-term adverse events following vaccination should be considered when planning the timing of vaccination for healthcare teams or other workers covering a specific service area.
All countries should continue to monitor the safety of vaccines and promote routine after-care following immunization, consistent with good immunization practices for any vaccine. The committee recommends that data on suspected adverse events should be collected and reviewed continuously – nationally, regionally, and globally – as the COVID-19 vaccines are rolled out, world-wide, in order to ensure their continuing positive benefit risk balance.
The GACVS subcommittee will continue to review the safety data from all COVID-19 vaccines and update any advice as necessary.
The WHO COVID-19 vaccine safety surveillance manual provides guidance to countries on the safety monitoring and adverse events data sharing for the new COVID-19 vaccines, and can be accessed here.
 At the time of this review, the WHO global Individual Case Safety Reports database, Vigibase, included reports of influenza-like illness following vaccinations with NRVV Ad (ChAdOx1 nCoV-19) (AZ), Tozinameran (Pfizer), mRNA 1273 (Moderna), COVID-19 vaccine inact (Vero) CZ02 (Sinovac) vaccines. WHO will continue to monitor for potential reports of similar events following other COVID-19 vaccines.