Childhood Immunisation

AN UPDATE ON THE IMMUNISATION SCHEDULE

In the first part of this article I will discuss the recently announced changes to the immunisation schedule. In the second part of the article I will discuss immunisation generally, including a brief synopsis of the nature of diseases we immunise for, and the benefits of immunisation.

What is changing in the National Immunisation Program ?

On 1st July 2013 the National Immunisation Program Schedule was changed.
The important changes to the schedule is that children will now receive a combined Measles, Mumps, Rubella and Varicella (Chicken pox) vaccine at eighteen months of age .

The commencement of the national Varicella (Chicken Pox) Vaccination Programme began in 2005. In this programme, children born on or after 1st May, 2004 received chicken pox vaccine free when they turn eighteen months of age.
All children will continue to be vaccinated for chicken pox at eighteen months. But the new vaccine will in effect bring forward the second dose of the vaccine for measles Mumps and Rubella which is normally due at four years of age.

As a result of the change children will not be given Measles, Mumps and Rubella vaccine at four years of age. Children will still continue to receive Diptheria,Tetanus, Pertussis and Injectible Polio vaccine at four years of age.

The introduction of a second vaccination for Measles Mumps and Rubella at eighteen months of age provides earlier two-dose protection of Measles Mumps and Rubella and is likely to result in an increased uptake of the second dose of the MMR and Varicella vaccine.

How will this change work ?

Children who have by 1 July 2013 already received their eighteen month Varicella vaccination should still be immunised for Measles, Mumps and Rubella (MMR) at four years of age.

This four year old scheduled vaccination point will remain until all children aged between eighteen months and four years of age as at 1 July 2013 reach the age of 4 years – that is 31 December 2015.

Children who have previously been infected with chickenpox should still receive the Varicella vaccination, as applicable to their circumstances on presentation.

The new vaccine to be introduced for Measles, Mumps, Rubella and Varicella vaccination is known as Priorix-Tetra (or MMRV).

MMRV must not be administered as the first dose of MMR given at 12 months. The twelve months MMR vaccine will remain as MMR or Priorix. The eighteen month vaccine will be a different vaccine MMRV or Priorix-Tetra.

While the decisions are made at a national level, there are variations in how the vaccines are delivered in each state. In this article I will deal with how the vaccines are delivered in NSW.

At the same time as the change in the national program, in NSW the two other vaccines which are delivered at the same time as the Measles Mumps and, Rubella at twelve months namely: Hiberix, the monovalent Hib vaccine for protection against illness caused by Haemophilus Influenzae Type B and Meningitec the vaccine for protection against the bacteria meningococcus type C are being combined into one vaccine known as Menitorix.

The vaccines in NSW are:

Infanrix-hexa
Australia’s first six-in-one vaccine will be provided free to all children at 2, 4 and 6 months of age. Infanrix-hexa protects against diphtheria, tetanus, whooping cough, hepatitis B, Haemophilus influenza type B (Hib) and poliomyelitis.

Prevenar13
For protection against disease caused by the bacteria pneumococcus provided free to all children at 2, 4 and 6 months of age.

Rotarix
Oral vaccine provided free to all children at 2 and 4 months of age for protection against diarrhoea caused by rotavirus.

Infanrix IPV
This is provided free to all children at 4 years of age. Infanrix IPV protects against diphtheria, tetanus, whooping cough and poliomyelitis.

Priorix
This is provided free to all children at twelve months and protects against Measles, Mumps and Rubella.

And of course the two new vaccines we have discussed.

Priorix-Tetra
This vaccine given at eighteen months protects against Measles, Mumps, Rubella and Varicella.

Menitorix
This is given at twelve months and replaces both: Hiberix which protects against illness caused by Haemophilus Influenzae Type B and Meningitec which protects against illnesses caused by the bacteria meningococcus type C.

WHAT IS IMMUNISATION?

Immunisation is a simple, safe and effective way of protecting children against harmful disease, before they come into contact with them in the community.

Immunisation means to receive a vaccine and for the body to mount an immune response to the vaccine. That is, when a person is injected with or swallows a vaccine, their body responds in the same way as it would after natural exposure to the disease, but without getting the disease. Therefore, if the person comes in contact with the disease in the future, the body is prepared and able to respond to that disease quickly enough to prevent the person getting sick.

WHAT IS A VACCINE?

The dictionary definition of a vaccine is a suspension of dead, attenuated, or otherwise modified micro organisms for inoculation to produce immunity to a disease by stimulating the production of antibodies.
Vaccines vary in their make up. Some vaccines contain a small amount of the virus which is weakened. Some vaccines contain a small amount of killed bacteria and some a small amount of modified toxin which is produced by the bacteria. The vaccines have other additives. Some contain small amounts of preservatives or antibiotics to preserve the vaccine and some contain an aluminium salt which helps enhance the immune response.

The terms vaccination and immunisation are often confused. Vaccination is the term used for giving the vaccine and immunisation is the process for mounting the immune response.

HOW LONG DO IMMUNISATIONS TAKE TO WORK?

Immunisation does not immediately protect the person from the disease. The normal immune response may take several weeks after vaccination and so it may be several weeks before protection occurs.

To build long-lasting protection, a child needs to be given a course of the vaccine and the time of subsequent doses is different for different vaccines. A child who has not completed the course for a particular vaccine is not fully protected and the course can vary depending on the age at which the child starts.

DOES IMMUNISATION ALWAYS WORK?

Even when a course has been completed, immunisation may not give complete protection. Measls,Mumps,Rubella,Tetanus,Polio and Haemophilus influenzae Hib vaccines protect more than 95% of children who have completed the course.

However, if the vaccine doesn’t give complete protection, it will certainly reduce the severity of the disease. Three doses of the Whooping Cough or Pertussis Vaccine will protect about 85% of children who have been immunised. The remaining 15% of children who are immunised, if they do contract the disease, should receive a less severe dose of the disease.

The effect of immunisation is not always life-long and so for some vaccines a booster dose is required.

DISEASES WE IMMUNISE AGAINST

The diseases we immunise against are :

DIPHTHERIA
Diphtheria is caused by bacteria which are found in the mouth, throat and nose of an infected person. Diphtheria can cause a membrane to grow inside the throat which can lead to difficulty swallowing and shortness of breath. A toxin can be produced by the bacteria which can cause paralysis and heart failure. About 7% of people who contract diphtheria can die from it. Fortunately, because of successful immunisation programmes, diphtheria is now rarely seen.

TETANUS
Tetanus is an often fatal disease cause by a bacteria which releases a toxin which attacks the nervous system causing muscle spasm usually first felt in the neck and jaw muscles causing ‘lockjaw’. It can cause breathing difficulties, convulsions and cardiac arrhythmias. Tetanus is present in soil and manure and enters the body from a wound in the skin which may be the size of a pin prick. Tetanus is rare in children today because of immunisation, but it still occurs in previously unimmunised adults.

WHOOPING COUGH / PERTUSSIS
Whooping Cough also known as Pertussis is a highly contagious bacterial disease. It is spread by coughing or sneezing. Pertussis attacks the airways and causes breathing difficulties. The child has severe coughing spasms and will gasp for breath between spasms. This gasping causes the characteristic ‘whooping’ sound. Complications of Whooping Cough can include convulsions, pneumonia, inflammation of the brain and permanent brain and lung damage.

POLIO
Polio is a severe viral infection of the nervous system. It causes paralysis of parts of the body. Since the introduction of polio vaccines, there as been a dramatic reduction in polio infection.

HEPATITIS B
This is a serious disease cause by a virus that affects the liver. The Hepatitis B virus is transmitted in infected body fluids including blood, saliva and semen. Babies whose mothers have Hepatitis B are at high risk of being infected at birth. When a person gets the disease, they may only have mild symptoms or no symptoms at all, but many will go on to carry the virus for many years. Twenty five percent of the people who carry this virus will go on to develop cirrhosis of the liver or liver cancer in later life.

MEASLES
Measles is a serious, highly contagious viral illness which causes fever, rash, runny nose, cough and conjunctivitis. Complications of measles include pneumonia and encephalitis. A very serious but rare illness called Subacute Sclerosing Panencephalitis (SSPE) can occur in children several years after measles infection. SSPE is a disease which rapidly destroys the brain and always results in death.

MUMPS
This is viral disease which causes inflammation of the salivary glands. It can cause meningitis and encephalitis. Mumps can cause permanent deafness and in adolescent and adult males it can cause infertility.

RUBELLA
Rubella , also known as German Measles, is a mild disease of childhood. It is highly contagious. Congenital rubella infection is a serious problem. This is where infection during the first twenty weeks of pregnancy can result in serious defects in the newborn including deafness, blindness, congenital heart disease and mental retardation.

HAEMOPHILUS INFLUENZAE TYPE B (Hib)
This is a bacterial infection which can cause life-threatening illnesses in children under five years of age. In addition to causing pneumonia and joint infection, Haemophilus Influenzae Type B can cause swelling in the throat of the epiglottis (epiglottitis) which can obstruct breathing and can also cause meningitis. In children, both these conditions can develop quickly and if not treated, will cause death.

MENINGOCOCCAL DISEASE
This is a serious disease cause by the bacteria meningococcus. It is spread by droplet infection. There is a vaccine for the C strain of the disease. Meningococcal disease is an uncommon but potentially life threatening infection that causes meningitis and septicaemia.

PNEUMOCOCCAL DISEASE
This is a serious disease cause by the bacteria pneumococcus. It can cause diseases such as ear infections (otitis media) or more serious disease such a s pneumonia, septicaemia and meningitis.

VARICELLA / CHICKEN POX

This is a mild but highly contagious viral disease. The virus responsible for Chicken Pox is known as Varicella Zoster. Chicken Pox usually causes a mild illness in children with complete recovery. More serious complications of Chicken Pox include encephalitis and pneumonia.

COMMON SIDE EFFECTS OF IMMUNISATION
Many children may experience minor side effects after immunisation. These side effects may include low grade fever, being unsettled, grizzly, generally unhappy, soreness or redness or swelling at the injection site. Measles, Mumps, Rubella vaccination may cause a head cold , runny nose, faint rash, fever or joint pains and swelling of the facial glands.

These symptoms may be concerning and cause the child discomfort, but the minor adverse effects of these immunisations by far outweigh the risks of the disease.

Generally speaking, if these symptoms do occur, it is important to give the child extra fluids to drink, not to overdress the child, and to give paracetamol to lower the fever.

Other side effects may occur and if you are concerned you should discuss these with your doctor at the time of immunisation.

WHAT YOUR DOCTOR NEEDS TO KNOW BEFORE YOUR CHILD IS IMMUNISED

The doctor needs to know if your child is unwell or has had a severe reaction to a previous vaccine, or has severe allergies.

If your child has had a live vaccine within the previous month (such as Tuberculosis, MMR, oral poliomyelitis or yellow fever vaccine) or an injection of immunoglobulin or a transfusion with whole blood, the vaccination may need to be delayed.

The doctor should be advised if the child has a disease which lowers immunity or is having treatment which lowers immunity such as treatment with medicine such as cortisone or prednisone, or if the child is having treatment with radiotherapy or chemotherapy. Certain medical conditions affecting the brain or spinal cord may mean the immunisation may be given a different way.

THE BENEFITS OF IMMUNISATION

Immunisation provides a safe and effective way of giving protection against disease and also the opportunity for the disease to be eradicated because if enough people in the community are immunised, the infection can no longer spread from person to person and the disease dies out altogether.

This is how Small Pox was eradicated from the world and why Polio has disappeared from many countries including Australia. Australia at the present time is in the process of certifying that it is free of polio as part of a global campaign to eradicate Polio. It is however still important to have children immunised against Polio.

Immunisation is there to protect your child.
Talk to your doctor today about the benefits of immunisation.

*The information given in this article is of a general nature and readers should seek advice from their own medical practitioner before embarking on any treatment.