What is immunisation?

Active immunisation is the use of vaccines to protect against particular diseases caused by bacteria or viruses.

What are vaccines?

Vaccines contain weakened, dead or (usually) fragmented viruses and/or bacteria that are responsible for some serious diseases. The body sees these fragments as foreign and develops an immune response (immunity) against them, without exposing the vaccinee (person receiving the vaccine) to the disease.

How does immunity work?

When a virus or bacteria enters our body, our immune system develops an immune response, which includes antibodies specifically against the virus or bacteria, to fight it. The first time an organism enters the body, the immune system is not ready and it takes some time to make antibodies. During this time we may become ill, however, if our immune system, including the antibodies, can control the organism we recover.

After infection, the immune system retains a memory of the infecting organism that attacked us, and if it enters our body again it is usually controlled before we become ill. Active immunisation using vaccines works in the same way - without us having to have the disease first.

Does my child need immunising?

Doctors worldwide believe it is essential that children receive a number of immunisations to prevent them getting serious childhood infections. Also, it is important for the community that as many children as possible are immunised, to prevent the spread of these diseases to other members of the community who may not be able to be vaccinated for various reasons.

In countries where immunisation is given to a very high number of people, the diseases can be controlled or eliminated from the population and the number of children who die of infectious diseases is dramatically reduced. Even if most of these diseases are now less common, they can come back at any time. New Zealand's immunisation rate is very low compared to many countries.

Where else does immunity come from?

We get immunity from many diseases by having them. However, that also means we usually get sick first. In some cases this is not serious, in others, the risk of serious illness is too high. That is why we vaccinate against some of the most serious diseases. Also, mothers pass on many antibodies to their babies both before they are born as well as in the breastmilk, if they breast-feed their babies.

Antibodies from the mother only last from weeks to months. Once they have gone, the child is unprotected from these infections. Breast-feeding does not protect a baby against many serious illnesses such as whooping cough (pertussis). It does, however, protect against some types of diarrhoea, vomiting, coughs and colds.

Is immunisation safe?

Vaccines must go through many tests before they can be used. The vaccines used in New Zealand have been proven to have excellent safety profiles and to be highly effective. Studies have shown that if all doses of vaccines are given properly they will protect 80% to 95% of the children who are immunised.

A number of children will have a minor reaction to immunisation. Serious reactions such as severe allergic reactions can happen, but are very rare. Your doctor is trained to handle such problems.

Some children who have been immunised may still become ill with the disease, but usually their illness is much less serious.

The risk from disease is far greater than the risk from immunisation. For example, one child in a million may get swelling of the brain after measles vaccination, while one in a thousand develops swelling of the brain from measles itself: of those, 15% will die and another 25% will have brain damage.

When should my child not be immunised?

If your child is having some medical treatments, has a serious disease or lives with someone with a severe disease, has an immune system that is not working properly or has had severe allergic reactions to immunisations before, or has recently had other vaccinations or blood treatments, immunisation may not be advisable.

Talk to your doctor. If the child has a cold or is a little unwell on the day of immunisation they can still be safely immunised. If they have a high temperature (over 38 degrees) or are very unwell, it may be better to delay the vaccination for a day or two.

What vaccines does my child need?

The New Zealand immunisation schedule from June 2008 is:

• DTaP-IPV-Hib-HepB (Diphtheria - Tetanus - acellular Pertussis - Inactivated Polio - Haemophilus influenzae type b (Hib) - Hepatitis B) at ages 6 weeks, 3 months and 5 months.
• PCV7 (Pneumococcal disease vaccine) at 6 weeks, 3 months, 5 months and 15 months.
• Children of Hepatitis B positive mothers also need an extra dose of Hepatitis B vaccine plus immune globulin at birth.
• MMR (Measles - Mumps - Rubella) + Hib (Haemophilus influenzae type b) at 15 months.
• MMR + DTaP-IPV at age 4 to 5 years prior to school entry.
• dTap (adult Diphtheria - Tetanus - acellular Pertussis) at age 11 years.
• Td (adult Diphtheria - Tetanus) boosters at 45 and 65 years of age or after some injuries if it is more than five years since the last booster - check with your local medical centre [a charge may apply for these boosters].
• BCG is given at birth to babies living in households with people who have, or have had tuberculosis (TB) or there are immigrants from countries where TB is common.

Vaccine key
DTaP = Diphtheria, Tetanus, acellular Pertussis
IPV = Inactivated Polio Vaccine
Hib = Haemophilus influenzae type b
HepB = Hepatitis B
PCV7 = Pneumococcal
MMR = Measles, Mumps, Rubella
dTap = Diphtheria, Tetanus, accellular Pertussis adult dose
Td = Tetanus-diphtheria - adult dose
ADT = Adsorbed Diphtheria, Tetanus. 

Special groups requiring additional vaccines:

• Premature babies: refer to IMAC for details.
• Birth: BCG vaccine for "at risk" babies. Hepatitis B vaccine plus hepatitis B immune globulin for infants of hepatitis B carrier mothers.
• **Annual influenza vaccination for adults and children from age 6 months with certain chronic medical conditions - (refer to IMAC)
• Women of childbearing age who are susceptible to rubella should be offered MMR vaccine.
• Children and adults before and after splenectomy (surgery to remove the spleen) will be eligible to receive pneumococcal, Hib and meningococcal vaccines.

Infanrix-hexa

The introduction of the Infanrix-hexa vaccine replaces the former two vaccines, Infanrix-IPV and Comvax. Infanrix-hexa thus provides the diphtheria, tetanus, acellular pertussis, inactivated polio vaccine, Haemophilus influenzae type b and hepatitis B dose (given at ages 6 weeks, 3 months and 5 months).

Infanrix-hexa begins on the immunisation schedule from June 2008, though some doctors may have been using this from March 2008, due to shortages with the former vaccines.

Pneumococcal vaccine (PCV7)

The PCV7 vaccine (Prevenar) - added to the immunisation schedule from June 2008 - protects young children against the seven most common strains of the Streptococcus pneumoniae bacteria that cause severe pneumococcal disease. All babies are at risk of severe pneumococcal disease, which can cause meningitis, blood poisoning and pneumonia. The pneumococcus is the most common bacterial cause of otitis media (glue ear) in children and a frequent cause of sinusitis and pneumonia in all age groups.

From June 2008, all new babies beginning their childhood immunisations will be offered the PCV7 vaccine. These babies will receive four doses of the PCV7 vaccine at the same time as other schedule vaccines at age 6 weeks and 3, 5 and 15 months of age. Babies born from 1 January 2008 will be eligible to receive PCV7 vaccine from 1 June 2008 and will receive a catch-up schedule for this vaccine.

High-risk pneumococcal immunisation programme

Children at high risk of pneumococcal disease may be eligible for the pneumococcal immunisation programme. From June 2008 this includes children aged under five years with the following conditions:

• on immunosuppressive therapy or radiation therapy, when there is expected to be sufficient immune response
• with primary immune deficiencies
• with HIV infection
• with renal failure, or nephrotic syndrome
• who are immune suppressed following organ transplantation
• with cochlear implants or intracranial shunts
• with chronic cerebrospinal fluid leaks
• who are receiving corticosteroid therapy for more than 2 weeks, who are on an equivalent daily dose of prednisone of 2mg/kg per day or more, or children who weigh more than 10kg on a total dose of 20mg or more
• before or after splenectomy (surgery to remove the spleen) or with functional asplenia (spleen not working)
• pre-term infants, born at under 28 weeks’ gestation
• chronic pulmonary (lung) disease (including asthma treated with high-dose corticosteroid therapy)
• cardiac disease with cyanosis (bluish discolouration of the skin and mucous membranes) or heart failure
• insulin dependent diabetes
• Down’s syndrome.
  

Special vaccination programme ends June 2008

Meningococcal B immunisation
Meningococcal disease is a bacterial infection. It causes severe illnesses including:

• meningitis (an infection of membranes that cover the brain)
• septicaemia (a serious infection in the blood).

The MeNZB™ vaccine was developed to protect against the strain of meningococcal B that caused the epidemic in New Zealand. Due to the immunisation programme (which started in 2004) the disease rates have reduced substantially and, from June 2008, the routine immunisation for children under five years will no longer be offered. However, those who started a course before this date are still recommended to complete it. For children or people at higher risk of the disease, the vaccine will still be available.

Future changes to schedule

HPV vaccine (Gardasil)

The human papillomavirus (HPV) vaccination programme will be introduced in stages. Girls born on or after 1 January 1990 will be eligible for the HPV vaccine. HPV is a sexually transmitted infection linked to the development of cervical cancer. HPV also causes genital warts. More information on HPV and cervical cancer.

From 1 September 2008

•  Girls aged 17 and 18 years (born in 1990 and 1991) will be able to receive the HPV vaccine (Gardasil) from primary care or health clinics.

From 2009

• HPV vaccine will be part of the National Immunisation Schedule for 12-year-old girls (in primary care and health clinics) and girls in school Year 8. 
• HPV vaccine will be offered to girls aged 13 to 18 years, phased in over 2009 and 2010.

What are these diseases?

Diphtheria

Diphtheria is a bacterial infection which affects the throat, making it hard to swallow and breathe. Children can become paralysed, develop heart failure or suffocate. The illness is now rare because of immunisation, but the bacteria is still around in some countries.

Tetanus

Tetanus is a bacterial infection which attacks the nerves and causes muscles to become tense and stiff. It lives in the soil and is picked up through skin wounds. If the breathing muscles are affected, it is serious and can be fatal. It is also now rare.

Whooping cough (pertussis)

Whooping cough, a serious bacterial infection of the chest, causes painful, difficult coughing. The cough is so severe that breathing is difficult and the child may vomit. Most children are well between coughing fits, but some get pneumonia, fits, coma, inflammation of the brain and brain damage. It is usually more severe in younger children, with young babies at highest risk of severe complications and death. It is still a common disease and there are outbreaks every three to five years.

From February 2006, 11-year-olds have received a booster of the whooping cough (pertussis) vaccine added to the diphtheria, tetanus vaccine dose (instead of at age 15 months as was previously offered on the immunisation schedule). This change was made as research shows adolescents to be at risk both of developing whooping cough and becoming carriers of the disease.

After the initial 3 doses of vaccine in infancy, two booster doses are given at a later stage, which maintains protection for a longer period. Receiving the second booster dose at 11 years thus offers protection throughout adolescence.

Younger children, who no longer receive the dose at 15 months, have their immunity boosted by the dose at age 4 years.

Hepatitis B

Hepatitis B virus infects the liver and causes fever, nausea, tiredness, dark urine and jaundice. Children usually only have mild symptoms but they are likely to become carriers and are at risk of liver disease and liver cancer later in life. Symptoms are usually more serious in adults.

Hepatitis is common in New Zealand, particularly among Maori, Pacific Islanders and some Asian groups. Each year, in New Zealand, about 100 people who carry the virus die from these illnesses. Children of mothers with hepatitis B must be vaccinated at birth.

Poliomyelitis

Polio is a viral infection of the nerves and it can paralyse different parts of the body, leaving the person permanently weakened. Because of vaccination, it is now rare in most countries, but is still found in some countries and can be passed on by travellers. Travellers should be aware there has been a resurgence in some countries which were previously polio-free, following false rumours that the vaccine spread HIV and caused infertility.

From January 2008 the polio dose was removed for 11-year-olds (they still receive the diphtheria-tetanus-acellular pertussis vaccine at this age). This is due to an earlier change to the schedule (in 2002) which means children receive their fourth polio dose at age four years.

Haemophilus influenzae type b (Hib)

Hib is a serious bacterial infection that can cause inflammation of the lining of the brain (meningitis), throat (epiglottitis) or many other conditions, including pneumonia. It has a death rate of about 3% for meningitis: many children who survive it have permanent nerve or brain damage. Before vaccination started in 1994, one in every 350 children under five became seriously ill with Hib.

From February 2006 the Haemophilus influenzae type b (Hib) vaccine has been used with the measles, mumps, rubella (MMR) vaccine at age 15 months.

Measles

Measles is a highly contagious common childhood disease that causes fever, runny nose, cough and eye infections. It can cause fits and lead to pneumonia or brain swelling causing damage or death.

Mumps

Mumps is also very common and causes fever, headache and swelling of the glands around the face. In adults and teenagers mumps may cause swelling of the testes and ovaries. It often causes swelling of the brain, but most children recover without a problem. Very rarely, it causes deafness or death.

Rubella

Rubella or German measles is common and is only a problem if women are infected in the first three months of pregnancy when it can cause serious damage to the developing baby. It is usually a mild illness in children, but in teenagers and adults can cause swollen glands, joint pain and a rash. Rarely, it may cause serious illness.

Tuberculosis (TB)

TB bacteria can infect any part of the body. There are often no symptoms at first and the infection can hide in the body and be stirred up again at any time. About 5% of infected people get lung or other problems. The condition is worse in children, the elderly or people with other diseases.

It is more common in Maori and immigrants from Southeast Asia and the Pacific Islands. Worldwide there is currently a resurgence of TB. Routine immunisation is no longer considered necessary but is given to high-risk infants.

What can I expect after immunisation?

The most common side effects are injection site pain and redness, sometimes a mild fever. Mostly, children will need reassurance and lots of cuddles. If they are hot, put them in light clothing and give them lots of fluids. Cool flannels over the injection site may help.

If your child has any unusual reactions or you are concerned, ring your doctor or practice nurse.

Does my child need an immunisation certificate?

All children born after January 1995 need an immunisation certificate. This lists the vaccinations recommended for all New Zealand children and shows whether your child has completed the full series. Your nurse or doctor will sign a certificate when the immunisations are completed at around 15 months.

A second certificate is issued once your child has had their follow up immunisations at around 4 to 5 years. If you decline immunisation the certificate can be signed by your nurse or doctor at any time.

Your child's early childhood centre, kohanga reo or primary school will need to see the certificate and record the information in a register. This register is checked by a Medical Officer of Health if there is an outbreak of disease in your area.

Children who have not been immunised will be offered immunisation. Non-immunised children may be asked to stay at home until the disease has gone, to help stop it spreading.

Further information and support

It is important that you fully understand the risks and benefits of immunisation, and discuss any questions or doubts you have with your doctor, Plunket nurse, local immunisation coordinator or the public health unit at your local public hospital.

Full information on all vaccines is available from the following groups and organisations:

• NZ Ministry of Health Manatu Hauora - website www.moh.govt.nz
• Immunisation Advisory Centre (see further below for contact details).

Original content provided by everybody. Material sourced from the Ministry of Health Immunisation Handbook. Updated and reviewed June 2008.