An ‘adverse event following immunisation’ (AEFI) is any detrimental health event which happens after a person receives a vaccine. A ‘health event’ is a symptom (something with a person complains of, for example a ‘headache’ or ‘difficulty seeing’) or a ‘sign’ (something a health practitioner notices about a patient, for example, raised blood pressure). The health event may or may not be caused by the vaccine. For example, the following are adverse events following immunisation: a person who receives a COVID-19 vaccine and then has a stroke, a heart attack or a death in a motor vehicle accident. Any of these events may or may not be associated with vaccination, but all of these events are ‘AEFI’. An AEFI usually occurs within 28 days following vaccination, but there is no time limit to reporting an event.

All health events after vaccination are important to investigate, because vaccines are given to healthy people. Therefore, whilst some mild and short-lasting symptoms are acceptable, moderately severe and severe side effects are not acceptable, and should be fully investigated to understand if the vaccination was responsible. If the public understands that all ‘adverse effects following immunisation’ are taken seriously, and appropriate action is taken, people will have more trust that vaccines are safe.

All vaccines (and medicines) have side effects. COVID-19 vaccines have mild side effects, which differ slightly among the vaccines that are available. Most COVID-19 vaccines cause mild fever or pain or redness at the injection site. Other side effects include high fever, fatigue, headache, muscle pain, rash at the injection site, chills, and mild diarrhoea. Most reactions to vaccines are mild and go away within a few days on their own. Allergic reactions (medically known as ‘hypersensitivity reactions’ are not uncommon after any kind of vaccine. Allergic reactions can be mild (such as a rash or itchiness around the injection site), or very uncommonly, severe. A severe allergic reaction known as anaphylaxis leads to low blood pressure, collapse, difficulty breathing with/without skin rash. This reaction needs emergency treatment including fluid, oxygen and adrenaline.

More serious or long-lasting side effects to vaccines have been reported but extremely rare. The most well publicised adverse reaction is a condition known as vaccine-induced thrombosis and thrombocytopenia (VITT). Symptoms appear 10-14 days after vaccination and may include symptoms of a stroke, or bleeding, and depend on which blood vessels and organs are affected. The exact mechanism of this is not clearly understood, but is likely to occur because of antibody responses to parts of the vaccine.

When adverse events are investigated, they are classified as:

  • Minor local reactions – these include swelling, redness or rash at the injection site
  • Minor systemic reactions – these include mild headache, body aches and pains, fainting or fever less then 38oC
  • Severe local reactions – these include longer duration of symptoms at the injection site, but also includes swollen glands or abscess at the injection
  • Severe systemic reactions – any condition that results in hospitalisation, severe allergic reactions, high and prolonged fevers or collapse

Theoretically, all adverse events after vaccination should be reported, even those that have improved clinically or resolved spontaneously. However, adverse events that occur commonly, such as mild fever, tiredness or headache are often not reported. Uncommon and serious side effects should always be reported. Serious adverse effects are those that need medical attention or admission to hospitalisation. In general, health authorities watch out for adverse effects that have proven associations with immunization, but also for adverse effects that may theoretically occur but which have not yet been observed.

Any health practitioner or member of the public may report that an adverse event following immunisation has occurred. When the vaccine is given at a vaccination station, the vaccinator or person responsible for the vaccination ‘station’ or the facility manager should report the adverse event.

The adverse event may be reported using the Med Safety App (see below) or by completing a paper ‘Case report form’ which may be found at immunization-aefi/. The form should be returned by email to

The best way for a member of the public to report an adverse effect is by using the ‘MedSafety App’ as described below.

The ‘Med Safety App’ may be found on Google Play Store (Android) or the App store (iOS). Instructions and a video explaining how to use it may be found at Health practitioners and members of the public may report the adverse event using the app. After the app has been downloaded, a person can report immediately, or register on the app by providing medical registration and contact details. 

The app will ask for details of the person reporting the event, so that the public health authorities can investigate the event. However, the patient details (the person who experienced the event) are not mandatory fields on the app. In this way the patient details will remain confidential and known only to the health authorities. If persons experience problems with the app, they may contact the helpline (012-501 0311 on weekdays during office hours) or send an email to

Each province and district has allocated persons who are responsible for investigating adverse events following vaccination. Usually these persons will belong to the ‘EPI team’ and/or the communicable disease surveillance team. The EPI team is responsible for co-ordinating the ‘Expanded Programme of Immunisation’ and is supporting the rollout of COVID-19 vaccines.

The person responsible for investigating the event will complete a ‘case investigation form’. This form asks a set of comprehensive questions that will provide all the information that is necessary to work out the relationship between the vaccine and the adverse events. Questions on the form include vaccination details and procedures, immunisation practices at the place where the vaccine was administered, cold chain and vaccine transport, community investigations (to identify clusters of cases), patient medical history, clinical examination and results of investigations. The investigator will obtain the medical records of the person who experienced the adverse event. The investigator will not make a judgement themselves on the cause of the adverse event, but will submit these data to the provincial or the national immunisation safety expert committee (NISEC).

The provincial committee responsible for reviewing the adverse event or NISEC uses the WHO algorithm to examine what is reported about the event, including the case investigation form, the patient’s clinical details, standard case definitions from the Brighton collaboration (, currently available literature regarding vaccine adverse events, and product-related data from the manufacturers. When all the data is put together, the committee categorises the event as being

  • ‘consistent with a causal association to immunisation’. This includes ‘vaccine product-related reactions, vaccine quality defect-related reactions’, ‘Immunisation error-related reactions’ or ‘Immunization anxiety-related reactions’.
  • a co-incidental event
  • temporally associated with vaccination but without definitive evidence for vaccine causing the event

This committee is appointed by the Minister of Health. It includes experts from all clinical disciplines whose expertise may contribute to determining the role of vaccines causing adverse events. Presently, experts on the committee include pharmacists, pharmacovigilance experts, infectious disease specialists, paediatricians, EPI programme experts, immunologists, microbiologists, pathologists, public health specialists. The committee may ask advice from specialists who do not sit on the committee. Meetings are held quarterly or adhoc depending on volume of cases that are reported.

The NISEC committee reports findings to the Minister of Health, the National Department of Health and the Provincial Departments of Health and to the South African Health Products Regulatory Authority (SAHPRA). NISEC adverse event data and final assessments are reported into the WHO so that pooled data from countries can contribute to global monitoring of safety signals. These data are reported via SAHPRA through the global ‘Vigibase’ and ‘Vigiflow’ database systems that are used to track adverse effects related to pharmaceutical and therapeutic treatments.

All COVID-19 vaccines that are currently administered are novel vaccines which are made available to people through the WHOs Emergency Use assessment and Listing procedures (EUALs). These are a set of procedures to evaluate health products for acceptable performance, quality and safety so as to accelerate the use of these tools during the epidemic. However, because products that are used under EUAL criteria are new products, there may be risks associated with the administration of these. Therefore, the WHO advised countries to ensure fair compensation through creation of ‘no fault compensation schemes’. A ‘no-fault’ compensation allows for a payout without the need to go to court to establish who was responsible (hence ‘no-fault’). Therefore it makes the compensation process faster and cheaper.

WHO has provided funds for countries that are beneficiaries of COVID-19 vaccines through the advance market commitment scheme. However, South Africa does is not eligible for this funding, and is obliged to provide our own legislative framework for compensation. The South African government has issued draft legislation under the Disaster Management regulations for public comment regarding a ‘vaccine injury no fault compensation scheme’. This scheme allows individuals who have suffered an adverse event to receive monetary compensation following review and investigation of the case by NISEC. The exact details of how the South African ‘no fault compensation process’ will work are being finalised.

For more information: Detailed information on COVID-19 vaccine adverse effects may be found at Email addresses of provincial persons who are responsible for investigation of adverse events following immunisation are listed below.

For assistance with the Med Safety App, please contact the helpline (012-501 0311 on weekdays during office hours) or send an email to


EPI manager

Provincial Surveillance officer

Eastern Cape

Free State





North West

Northern Cape

Western Cape