Questions and Answers regarding the Immunisation Schedule..
Why
is the schedule being changed ?
The last full immunisation schedule change was
in 1996. Since then newer vaccines
have become available that are safer and effective in controlling preventable
diseases. The oral polio vaccine is
being replaced by the injectable inactivated polio vaccine which is given in
conjunction with the DtaP. The
Ministry of Health is able to make this change as Dtap-IPV has been licensed and
is available in New Zealand. It is
expected that this change will prevent the rare cases of vaccine-associated
paralytic poliomyelitis in recipients and non-immune contacts.
The vaccinations that children will receive at
four years of age will assist in preventing outbreaks of pertussis being spread
through primary school aged children.
Is
immunisation compulsory ?
Immunisation is not compulsory in New Zealand
and there are no plans of making it so. However,
immunisation is highly desirable and we strongly recommend that children are
fully immunised before starting school. There is research showing that unimmunised children spread
these infections to younger family members.
Schools are required to ask parents to show each new entrant's
Immunisation Certificate and to keep an immunisation register.
Information on the Certificates is given in a pamphlet entitled
"Immunisation Certificates - Information for Primary Schools" which
all schools have. Parents and
caregivers have the right to make informed choices about immunisation.
They need reliable information about the nine diseases which immunisation
protects against, and the effectiveness and side effects of the vaccines.
Immunisation if free, and protects against
measles, mumps, rubella, polio, whooping cough, diphtheria, tetanus, Heamophilus
influenza (Hib) and Hepatitis B. Research
has proven the risk of complications form catching these diseases is far greater
than the side effects from vaccines.
COMMONLY
ASKED QUESTIONS ABOUT IMMUNISATION
'Vaccines
do not work as most cases of the disease are in immunised children'
No vaccine is 100% effective and some immunised
children will get the disease. As
immunisation coverage increases the proportion of cases who are immunised will
increase. There is a simple
relation between vaccine efficacy, immunisation coverage and the proportion of
cases who are immunised. Imagine a
group of 100 children. If 90% of
children are given a vaccine that is 90% effective, that means that 81 of the
100 will be immune. So 10 children
will be susceptible from not having the vaccine and another 9 from vaccine
failure. So, nearly half the cases
of disease will be in immunised children - even though only 10% of immunised
children were susceptible.
'Immunisations
are not needed in industrialised countries'
Many diseases prevented by immunisation are
spread directly from human to human therefore clean water and good hygiene do
not stop all infections (e.g. measles, pertussis). Despite excellent hospital care, long term complications and
death still occur from diseases that can be prevented by immunisation.
While it is true that the impact of immunisation is greater in less
developed countries, it remains important for New Zealand children.
'Natural
immunity better than vaccine-induced
immunity'
No. Although
protective antibody levels tend to be higher after disease than immunisation
this does not necessarily mean that natural immunity is better.
There is more to immunity than antibody levels.
Natural immunity and vaccine-induced immunity
are both natural responses of the body's immune system.
The body's immune response in both circumstances is virtually the same.
The problem is that with 'natural' disease, your child runs the risks of
serious illness, disability and death to get immunity.
In contrast, immunity from vaccine is at a much lower risk. However,
several doses of the vaccine (as well as Booster doses) may be needed to achieve
and maintain good levels of immunity. Immunisation
does not always produce immunity.
'A
healthy lifestyle will protect children from infection'
A healthy lifestyle does not produce the
necessary immune response to protect a child from serious infection.
Only immunisation or actually catching the disease can do this.
Immunisation poses far less risk than
catching the infection and maintains the health of the child.
The living arrangements of a person (e.g.
overcrowding, in adequate sanitation and hygiene) will affect the likelihood of
being exposed to an infection. The
health of a person makes little difference as to whether they will get an
infection if exposed. However, a
child who is in good health will be much less likely to suffer a severe illness,
or to have complications.
A healthy lifestyle does not provide secure
protection against disease or its complications. For example, over half of all the children who died
from measles in the UK between 1970 and 1983 were previously healthy (Miller
1985). In the 1991 measles epidemic
in New Zealand there were seven deaths, five children, and two. No other contributing condition was listed in the death
certificates.
'Homoeopathic
immunisation prevents infection'
Homeopathic 'immunisation' offers no proven
protection against infectious diseases. Dr
Hahnemann, the founder of homeopathy, considered conventional immunisation to be
'a clear and convincing demonstration of the Law of Similitude' - the
fundamental principle of homeopathy (Fisher 1990).
The UK Faculty of Homeopathy supports conventional immunisation and is
not aware of any evidence supporting the use of homeopathic immunisation
(English 1992).
Some non-medical homeopaths do not support
conventional immunisation and state that homeopathic preparations can prevent
disease. There are no published
studies to support such beliefs. In
addition, an extensive review of homeopathic studies found none on the
prevention of the immunisation schedule diseases (Kleijnen et at 1991). There were some studies on the prevention of influenza, with
all but one showing no effect. The
one study that did find a protective effect was rated as 'poor quality'.
Only conventional immunisation has been shown to
produce a measurable immune response and protection against disease.
'Vaccines
contain toxic chemicals, viruses and cells'
The production of a vaccine is highly regulated,
with a requirement for extensive testing during manufacture and of the final
product. The manufacturer must show
that each dose if safe, pure, and potent enough to be effective.
Any toxic substances (e.g. formaldehyde) that are present can only be in
very small amounts, considerably less than are likely to do any harm to a baby.
There have been unwanted viruses in vaccines in
the past: such as SV40 in polio vaccines in the 1950s and Pestivirus in some
Japanese vaccines in the 1980s. All
vaccines are carefully tested now to ensure that there are no other viruses or
bacteria present. The
sophistication of this testing continues to improve.
In 1995, there was concern at the finding of an
enzyme (reverse transcriptase) in vaccines grown in chick cells that could have
come from a previously unidentified virus.
The finding was from a new test that was a million times more sensitive
than the old test. Further work has
identified the source of this enzyme as from the chick cell that the vaccine is
grown in, rather than any virus (Anonymous 1998).
Some vaccines (e.g. rubella) are grown in cells
of human origin. The starting
material for some of these cells was from foetuses aborted for medical reasons
in the 1960s. By a process of
repeated cultivation it is possible to produce an 'immortal' self-replicating
group of cells known as a 'cell line'. A
cell line is similar but not identical to the original cell.
Apart from the origin of the cell there is no other connection to any
foetus. The cell line can be
maintained indefinitely in the laboratory and provides a safe and standardised
medium for growing vaccine viruses.
Whether the vaccines are grown on cells of human
or animal origin, the cells are not in the final vaccine.
Once the vaccines have been grown on the cells, they are separated from
the cells, and all the cells' materials are removed.
It is possible that minute traces of parts of these cells would remain in
the vaccine, but it would not be possible for any whole cells to be in the
vaccine.
'Vaccines
may cause mad cow disease'
The materials used in some vaccines could, in
theory, transmit Bovine Spongiform Encephalopathy (BSE) or mad cow disease or
its human equivalent variant Creutzfeld-Jakob Disease (vCJD).
After billions of doses of use, this has not been documented.
In addition, for those vaccines that use material from cows (e.g. Hib
vaccine) the manufacturer must ensure that these materials come from BSE free
areas and that it is purified to reduce any risk.
There is also a theoretical risk from vaccines that use human blood
products such as albumin (e.g. MMR). Again,
this has never been demonstrated. In
addition, there is no evidence of transmission of vCJD from blood products.
'Vaccines
viruses persist after immunisation'
Vaccine viruses are supposed by some opponents
of immunisation to persist in the body leading to chronic disease.
There is no evidence that constituents of vaccines persist after
immunisation. Varicella vaccine
(chickenpox) does persist after immunisation and may rarely cause shingles.
Varicella is not currently on the New Zealand immunisation schedule.
'MMR
can cause autism and inflammatory Bowel Disease'
Recent studies proposed that the measles vaccine
is linked with inflammatory bowel disease and autism whilst other reports have
found no such association. The
recently released Institute of Medicine report from the Immunisation Safety
Review Committee, MMR and Autism in the US, concluded that the evidence does not
support, at the population level, a causal relationship between the MMR vaccine
and autistic spectrum disorders (ASD). The Committee does not exclude the possibility that the MMR
vaccine could contribute at ASD in a small number of children. This
is because of the difficulty of assessing a rare occurrence and proposed
biological models have not been disproved (Institute of Medicine 2001). The committee did not recommend any review of licensure of
MMR or change in the programme in the US.
'My
child is allergic'
Only anaphylaxis is considered a
contraindication or precaution for immunisation. Children with asthma, eczema, hay fever and simple allergies
should be immunised in the usual way. Egg
allergy is no longer considered a contraindication to vaccination (Khaakoo
2000). Other components of the
vaccine, for example gelatine, may be responsible for the allergic reactions
(Nakayama et al 1999).
References
Miller C.L. 1985. Deaths from measles in England and Wales.
1970-83.
British Medical Journal 290: 443-4.
Fisher P. 1990. Enough nonsense on immunisation.
British
Homeopathic Journal 79:198-200. - The Fundamental
Principle of Homeopathy.
English J. 1992. The Issue of Immunisation.
British
Homeopathic Journal 1992; 81: 161-3.
Kleijnen J, P. Knipschild P, ter Riet G. 1991.
Clinical trials of homeopathy.
British
Medical Journal 302:316-23.
Anonymous.
1998. Reverse transcriptase
activity in chicken-cell derived vaccine.
Weekly
Epidemiology Rec 73: 209-12.
Institute of Medicine.
2001. Immunisation Safety
Review Committee: MMR and Autism.
Khaakoo GA.
Lack G. 2000. Recommendations
for using MR vaccine in children allergic to eggs.
British
Medical Journal 320: 929-932.
Nakayama T, Aizawa C, Kuno-Sakai H. 1999.
A clinical analysis of gelatin allergy and determination of its causal
relationship to the previous administration of gelatin-containing acellular
pertussis vaccine combined with diphtheria and tetanus toxoids.
Journal
of Allergy Clinical Immunology 103: 321-5.
For more information contact:
1. The
Ministry of Health Website www.moh.govt.nz
2. 0800
IMMUNE (0800 466 863), or see the Immunisation Advisory Centre website
3. Your local Immunisation coordinator or Public Health Service.
4.
The practice nurse at the clinic: 578-1665
