HAEMOPHILUS INFLUENZA B -THE DISEASE AND THE VACCINE
YOUR QUESTIONS ANSWERED BY DR JAYNE DONEGAN
Informed Parent Summer 1997
1. Are the symptoms the same as those from other forms of meningitis?
The symptoms of Haemophilus Influenza B (Hib) meningitis are similar to those of other forms of meningitis in children. Hib meningitis occurs more often after colds, coughs and ear infections in young children. Seizures are more common. The disease tends to have a slower onset than Neisseria meningitidis type B meningitis and is less likely to cause a rash. It also occurs less commonly in epidemics.
2. What other diseases does the vaccine prevent and how does it cover more than one?
Haemophilus influenzae is a bacterium that infects humans only. It comes in an unencapsulated form which causes mostly coughs, colds. sinusitis and ear infections. There is an encapsulated form that has six types (A-F). Type B is the commonest type and can cause invasive disease. It may spread directly and inflame the skin of the face or cause epiglottitis or it may invade the blood stream and cause infections further away - meningitis, joint infection, pneumonia. 90% of healthy individuals carry Haemophilus influenzae in their noses. 5% of these organisms will be type B.
The vaccine is only against type B so it will only affect infections caused by Haemophilus influenzae type B (Hib). It is also likely that, as infections by type B are suppressed, the other types A, C-F will eventually take over and produce them instead.
3. Is my child less likely to get Hib meningitis because other children are vaccinated or more likely to because the other children are carrying Hib without signs of illness?
Invasive Haemophilus influenzae disease is more likely in children aged 3-48 months. The peak age is ten to eleven months. Antibodies form against the encapsulated form (of which type B is one) and may be the result of carrying the organism, without symptoms, in the nose or the pharynx. Antibodies may also be formed as a result of infections with other organisms that have similar capsules (such as E. coli k100, found in the gut).
The vaccine will presumably cause less children to meet the organism and less children to carry it in their nose. This means that less children will gain natural immunity to Haemophilus influenzae and this will increase the likelihood of their contracting severe forms of the disease at a later age.
The incidence of disease caused by invasive forms of Haemophilus influenzae (encapsulated forms A-F) has been rising since the introduction of mass vaccination in the 1950s and excessive use of antibiotics.
In answer to the question, your child may be less likely to get natural immunity from meeting the infection in other children but, hopefully, should still meet it in healthy adult carriers. As this latter group disappears with the vaccination of sucessive generations, the chance of gaining natural immunity at an early age will also disappear with all the consequent complications that this causes.
4. What studies have been done on reactions and long term effects? How long has the vaccine been available?
Studies have been carried out on reactions but none of them are long term. The original vaccines were unconjugated and did not produce an immune response in children less than 18 months of age. The current conjugated vaccines are made of a purified part of the capsule of Hib and are joined (conjugated) to another material with the aim of provoking an immune response at a younger age.
The conjugated vaccines have been around for less than ten years and were not licensed for use in two month old children until 1990 (in the USA). There are many different types, depending on the material to which they are conjugated:
PRP-D Conjugated to Diphtheria Toxoid
PRP-T Conjugated to Tetanus Toxoid (Pasteur Merieux - ActHib and ActHibDPT)
PRP-CRM Conjugated to Cross Reacting Mutant Diphtheria Toxoid (Lederle Praxis CRM 197 HibTITER)
PRP-OMP Conjugated to Outer Membrane Protein of Group B Neisseria meningitidis
HbOC Conjugated to Oligosaccharide
The Handbook of Immunisation against infectious diseases 1996 mentions large field trials in Finland, the USA and the UK. The trials showing the highest efficacy and given as references in the Handbook are for the vaccines PRPOMP and HbOC, neither of which are used in this country. The trials were all over a one to two year period so no data as to long term efficacy are available. As for reactions, studies on reactions and incidence of Hib disease post vaccination have been mainly in children who were given Hib vaccine and DPT and Polio compared with children given DPT and Polio alone. This is not a very good control group, bearing in mind the high incidence of adverse effects that these vaccines have on immunity, particularly in young babies.
Some studies suggest that the Hib vaccine may reduce the ability of a child to fight infection in the two to three weeks after administration.
The Handbook on Immunisation mentions swelling and redness at the injection site in 10% of doses. The British National Formulary lists: fever, headache, malaise. irritability, prolonged crying, loss of appetite, vomiting, diarrhoea, rash, allergic urticaria, convulsions, erythema multiforme, and transient cyanosis (blueness) of the lower limbs. Other reactions which have been reported through the Vaccine Adverse Event Reporting System (VAERS) of the USA are: Guillain-Barré Syndrome (a neurological disease which may eventually cause paralysis of the muscles needed for breathing and necessitates artificial ventilation in intensive care. .The symptoms may gradually improve), Transverse Myelitis (a paralysing disease that mainly involves the legs), Death (which may have been caused by the Hib vaccine or by other vaccines that were given at the same time).
5. At what age is one less likely to contract a Hib disease? Is this because of a more developed immune system?
Hib disease is unlikely to occur after the age of five years because by this age the organism will have been encountered and symptomatic or asymptomatic disease with subsequent immunity will have occured, but this age will rise as vaccination becomes more prevalent. 70% of all cases of Hib and menigococcal type B meningitis currently occur in children less than five years of age. Boys are more likely to be affected than girls. The highest seasonal incidence is between autumn and spring. The incidence is much higher in daycare institutions.
6. What can I do to boost my childs immune system? I want to give them vitamins but can only find inadequate synthetic ones.
To boost your childs immune system you need to give them love, time (ordinary time not just quality time), fresh air, fresh fruit and vegetables, home cooked, unprocessed food, water (uncontaminated by sewage, heavy metals and agrochemicals), exercise and the space to assimilate all that is going on around them in this increasingly hectic, unchildlike world.
VITAMINS. Because of intensive farming methods and pollution, it is probable that even a healthy, well balanced diet is lacking in nutrients. Vitamin supplementation is, therefore, probably advisable. Natures Own (Tel 01684 310022) make what they call food state vitamins which are supposed to be more bioavailable. Unfortunately, they charge more for their childrens multivitamin/mineral supplements than they do for their adult ones (even though there is less in them!) because of their odd package sizes. If you do wish to order something from them, ask to speak to the managing director, Peter Wallace, and insist that you get 100 childrens vitamins for the same price as 100 adult ones.
Jayne L M Donegan,July 1997
Handbook of Immunisation against Infectious Disease -1996 HMSO
British National Formulary, Number 33 - March 1997 BMA and Royal Pharmaceutical Society of Gt Britain
Harrisons Principles of Internal Medicine, 11th Edition -1987 McGraw Hill
Vaccination, Viera Scheibner -1993 Australian Print Group, Victoria, Australia
The Vaccination Guide, Randall Neustaedter - 1996 North Atlantic Books, Homeopathic Educational Services, Berkley, California, USA