Published: 21 April 2021


Adverse events following immunisation with COVID-19 vaccines: Safety Report #3 – 20 March 2021


This page provides information on the number of adverse events following immunisation (AEFI) reports received for COVID-19 vaccines.

The national roll-out of COVID-19 vaccines commenced on 20 February 2021. The vaccine currently available in New Zealand is Pfizer-BioNTech (Comirnaty). All medicines can cause side effects, the known side effects for Comirnaty are listed in the data sheet and consumer medicine information.

Suspected AEFI to COVID-19 vaccines are reported to the Centre for Adverse Reactions Monitoring (CARM). The Ministry of Health (through Medsafe) contracts the collection of this information to CARM, based at the University of Otago in Dunedin. Medsafe is closely monitoring the AEFI reported from the use of the COVID-19 vaccine. Find out more about vaccine safety monitoring.

Adverse events following immunisation (AEFI) reported

The number of AEFI reports, reports by age band and vaccine dose and the top 10 most frequently reported AEFIs by vaccine dose are provided below. Medsafe expects to provide some ethnicity information in the coming weeks.

AEFI reports received and vaccine doses administered, up to and including 20 March 2021


New AEFI reports since last update

(83 new non-serious and 4 new serious)


No safety signals (potential safety issues) have been identified


Total doses administered



Total AEFI reports that were non-serious


Total AEFI reports that were serious


Total AEFI reports that were received


There were 83 new non-serious and 4 new serious cases reported since the last update. The 4 serious reports were allergic reactions and were managed appropriately.

AEFI reports received by age band and vaccine dose, up to and including 20 March 2021

Age Dose 1 Dose 2 Dose
10 - 19 years 11 0 0 11
20 - 29 years 63 7 6 76
30 - 39 years 53 6 8 67
40 - 49 years 46 6 3 55
50 - 59 years 55 5 5 65
60 - 69 years 17 0 3 20
70 - 79 years 2 0 1 3
80+ years 0 0 0 0
Unknown 1 1 3 5
Total 248 25 29 302

Top 10 most frequently reported AEFIs, any dosea, up to and including 20 March 2021

Reaction Number
Dizziness 72
Headache 58
Nausea 53
Fever 22
Vasovagal/Syncopeb 22
Myalgiac 18
Fatigue 17
Arm pain 16
Faintness 13
Chills 12


  1. Includes AEFIs reported for dose 1, dose 2 or dose unknown
  2. Vasovagal/Syncope: fainting
  3. Myalgia: muscle pain

Top 10 most frequently reported AEFIs, dose 1 only, up to and including 20 March 2021

Reaction Number
Dizziness 59
Nausea 40
Headache 36
Vasovagal/Syncopea 22
Faintness 11
Swelling 10
Feeling of warmth 8
Arm pain 7
Fever 7
Flu-like symptoms 7


  1. Vasovagal/Syncope: fainting

Top 10 most frequently reported AEFIs, dose 2 only, up to and including 20 March 2021

Reaction Number
Headache 9
Fever 7
Myalgiaa 7
Dizziness 6
Nausea 6
Chills 5
Fatigue 5
Arm pain 4
Musculoskeletal pain 4
Flu-like symptoms 3


  1. Myalgia: muscle pain

Please note that one adverse event report, which represents one person, may report on more than one symptom. Reports are sent to CARM if the reporter suspects that the vaccine may have caused the event. This does not necessarily mean that the vaccine did cause the event.

The number of reports can be influenced by how many people are being vaccinated, media attention, the nature of the events (eg, how painful the vaccination was), and other factors which vary over time. Not everyone who has an adverse reaction reports it, and some people may report AEFIs after each vaccination. The information here shows the number of reports not the number of people who experienced an AEFI.

The information is limited by the information provided in the report and may change over time due to quality control procedures and/or receipt of additional information. Non-valid reports are not included in the data.

Medsafe and CARM thank everyone who has contributed to the monitoring of COVID-19 vaccines. Please continue to report any adverse events following immunisation.


Adverse event following immunisation (AEFI)
An AEFI is an untoward medical event which follows immunisation and does not necessarily have a causal relationship with the administration of the vaccine. The adverse event may be an unfavourable or unintended sign, abnormal laboratory finding, symptom or disease.
Serious adverse event following immunisation
An AEFI is considered serious if it:
  • is a medically important event or reaction
  • requires hospitalisation or prolongs an existing hospitalisation
  • causes persistent or significant disability or incapacity
  • is life threatening
  • causes a congenital anomaly/birth defect
  • results in death.
It is possible for different people to have experienced the same event but for the report to be serious for one person and non-serious for another person.
Safety signal
Information on a new or known adverse event that may be caused by the vaccine and requires further investigation. Safety signals can be detected from a wide range of sources such as CARM reports, clinical studies and scientific literature.
Valid report
There are only four requirements for a valid AEFI report:
  1. one patient identifier (eg, name, initials, gender, date of birth, age)
  2. suspect medicine(s)
  3. suspected reaction(s)
  4. reporter details.
These four requirements are the minimum requirements. However, including more information in the report helps Medsafe to investigate the reaction more quickly. Reporting is easiest online.

More information

See the data sheets and consumer medicine information for the expected reactions for approved COVID-19 vaccines.

COVID-19 Vaccine Safety Monitoring Process

View Ministry of Health COVID-19 vaccine data

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