Vaccine safety monitoring

Like all medications, vaccines have potential side effects, sometimes called ‘adverse events following immunisation’ (AEFI) by healthcare professionals.

However, unlike other medications that are given to a small number of people to treat a disease, vaccines are given to a large proportion of healthy people to prevent a disease. 

For this reason, they are held to a higher safety standard than other medications. Read more about pre-clinical trials and clinical trials of vaccines under development.
 

Safety monitoring after vaccine approval

Once vaccines are approved and being used in the general population, ongoing vaccine safety surveillance occurs. 

This identifies and investigates:   

• rare side effects that may not have been detected during clinical trials  
• AEFI rates/profiles in specific populations that may not have been included in clinical trials (such as pregnant people or people with specific medical conditions)
• unexpected increases in known side effects that may indicate a safety concern related to the vaccine product or vaccine quality defect. 
   

Spontaneous (passive) surveillance

The Therapeutic Goods Administration (TGA) collects reports of side effects and other safety concerns following vaccination. These reports come from healthcare professionals, pharmaceutical companies, state and territory health departments – and the public.

To make sense of all reports, the TGA may ask the reporter for more details. 
 

How reports are managed

All reports of serious AEFIs are looked at by a TGA vaccine safety expert. If a reported serious AEFI could change the benefit–risk profile of a vaccine or affect public confidence in the vaccine, a meeting of vaccine experts (Vaccine Safety Investigation Group [PDF]) is called to investigate and manage the case(s). 
 

Recognising safety issues through data

In addition to individual case reviews, the TGA also identifies potential safety issues by looking for patterns in the data using data-mining algorithms.
 

Recognising safety issues through other agencies

The TGA also looks for safety issues from other agencies (including AusVaxSafety, state and territory health authorities, international regulators or pharmaceutical companies).  
 

Safety investigations

When a possible safety issue is found, the TGA investigates.

TGA safety investigations involve looking at and comparing:

• individual AEFI reports
• number of cases nationally (observed rate)
• expected number of cases based on past data without vaccination (expected rate). 

The TGA also looks at: 

• the World Health Organization global vaccine safety surveillance database
• published reports
• research into how the vaccine could have caused the AEFI (biological plausibility).  

Findings are used to work out if the vaccine product information sheet or vaccination program recommendations need to be updated. 
 

Active surveillance

Active vaccine safety surveillance involves directly engaging with vaccine recipients to actively solicit information on AEFI and complements the spontaneous reporting system. 

AusVaxSafety is Australia’s active vaccine safety surveillance system and has undertaken active vaccine safety surveillance since 2014. 

How AusVaxSafety works