Vaccine Safety Information
Vaccination has proven to be an essential intervention to prevent many deadly infectious diseases and is estimated to save millions of lives world-wide each year. However, like any medicine, very rarely vaccines may cause side effects.
Common and Minor Vaccine Reactions
The purpose of a vaccine is to induce immunity by causing the recipient’s immune system to react to the vaccine. Local reactions, such as low to medium grade fever and other more general symptoms can result as part of the normal immune response. In addition, some of the vaccine’s components added to facilitate storage (such as the vaccine preservative) may induce a reaction of their own in the injection site.
It is important to note that most of the minor common symptoms are only temporary and expected as a normal response of a healthy immune system to the vaccine. The vaccines used in the National Immunisation Program have been formulated so that reactions are kept to a minimum while producing the best possible immunity.
Local reactions include pain, swelling and/or redness at the injection site and can be generally expected in about 10% of individuals who receive vaccines. Some vaccines such as diphtheria, tetanus and pertussis vaccine (DTP), or tetanus boosters may cause reactions in up to 50% of the people who receive them.
Generalised reactions are more common in live attenuated (weakened) vaccines (such as MMR), where bodily responses such as fever, irritability, rash, malaise, feeling ‘off-colour’ and loss of appetite may occur as part of the mild version of the “real” disease. Such reactions may occur in about 5-10% or less of people receiving a vaccine. These symptoms are very mild when compared to severity of the disease caused by the infection of the "wild" virus.
The rates of occurrence of such common local and generalised symptoms are still monitored continuously by the TGA (as well as by the regulatory body in the various countries around the world) as part of the ongoing vaccine safety surveillance activities. If a significant increase of these observed rates for any vaccine is detected, investigations take place to exclude possible adverse reaction to the given vaccine.
For further information on the common minor vaccine reactions for each vaccine found on the National Immunisation Program, please see the table below.
For practical hints and tips about how to accurately measure a child's temperature, please visit the Seattle Children's Hospital Foundation website.
A contraindication of live attenuated vaccines are conditions involving severe immuno-deficiencies. A compromised immune system cannot cope with the exposure to infectious disease, even if caused by a weakened virus - in fact vaccination in these individuals may cause severe or even fatal complications. This is why these individuals rely on other people (the "herd') to be immunised and create a shield of protection around them - this is the concept of herd immunity.
To learn more about this concept please see a great video on herd immunity.
How Do I Find out about Side Effects for Different Vaccines?
When you or a child receive a vaccine, the health care provider may provide you or you may request to be provided with a leaflet describing common and rare side effects.
You can also view a very useful information sheet comparing the effects of diseases and the side effects of vaccines on the National Immunisation Program, from The Australian Immunisation Handbook.
Further details about the side effects associated with the different vaccines can also be found in what is called the Consumer Medicine Information (CMI).
The table below summarises the common minor side effects after vaccination. It is important to remember that the discomfort often experienced around the vaccination site (such as redness and tenderness) are just a sign of a healthy immune system.
||When this may develop
|Diptheria-tetanus-pertussis||Infanrix IPV, Infanrix hexa||Mild fever, swelling or soreness at the injection site||Within 4 hours|
|Haemophilus influenza type b||Menitorix||Mild fever, swelling or soreness at the injection site||Within 4 hours|
|Hepatitis B||HB Vax II||Mild fever, soreness at the injection site, nausea, malaise, muscle or joint pain||Within 4 hours|
|Human papillomavirus||Gardasil||Fever, tenderness or swelling at the injection site, nausea||Within 4 hours|
|Influenza||Flurix, Influvac, Vaxigrip||Mild fever, swelling or soreness at the injection site||Within 4 hours|
|Measles, mumps and rubella||MMR II, Priorix, Priorix tetra, ProQuad||Mild fever, rash, swollen glands||Between 5 to 12 days after vaccination|
|Meningococcal C||Menitorix||Pain, redness and swelling at injection site, fever, irritability, headache||Within 4 hours|
|Pneumococcal||Prevenar 13||Mild fever, swelling or soreness at injection site||Within 4 hours|
|Rotavirus||Rotarix, RotaTeq||Mild fever, diarrhoea||Within 7 days|
|Varicella||Priorix tetra, ProQuad||Mild fever, rash, swelling or soreness at injection site||Within 0 to 42 days|
Myths About Vaccines
Vaccination is a safe and effective intervention in keeping populations around the world free from diseases, such as poliomyelitis, measles and whooping cough. However, misinformation regarding the safety of vaccines has resulted in decreased public confidence, leading to reduced vaccination rates and and the reappearance of dangerous and highly contagious vaccine-preventable diseases. This was case of measles in the United Kingdom in 1998 following concerns about the measles-mumps-rubella (MMR) vaccine and autism.
Vaccination Myths Video
Discover the truth as this video explores some common vaccination myths, including the mercury (i.e., mercury-based preservative thiomersal) fear and autism claims.
Credit: Australia's Science Channel
Thiomersal content in childhood vaccines
Thiomersal is a preservative that contains mercury. For decades it was used in vaccines and proven to be safe. However, to remove any possible controversy, from 2000, thiomersal was removed from all childhood vaccines administered in Australia,
Please read the NCIRS factsheet for more information on thiomersal.