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An afternoon with immunisation expert, Professor Margaret Burgess |
 Professor Burgess is the director of the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Westmead. She is also a paediatrician at the New Children’s Hospital, Westmead, and professor of paediatrics and preventive medicine, University of Sydney. She met with GPs on her recent visit to the the Northern Rivers in July. The following are excerpts from her talk, which is available on loan from the NRDGP on video.
Q. What is the latest news in vaccine development?
There’s a whole range of new vaccines that are going to be marketed in the next two years. First of all there is a series of combination vaccines. Commonwealth Serum Laboratories has a five in one vaccine - whole cell pertussis, diphtheria, tetanus, Hib and hepatitis B - that will be marketed. It is not going to be a preferred vaccine because it has whole cell pertussis in it, but an acellular combination vaccine containing Infanrix and hepatitis B will be on the market before the end of the year and that is likely to be included in the new national schedule.
We will also see a whole lot of combination vaccines in the next few years, which will probably amount to a six in one and possibly a seven in one, but for the immediate future we have the possibility of this whole cell pertussis, diphtheria, tetanus, Hib and hepatitis B, which will be a very useful vaccine.
Within the next 12-18 months we will have varicella vaccine as a single shot licenced in Australia - a single shot under the age of 13 and two vaccinations a month to six weeks apart over the age of 13. And probably towards the end of next year a rotavirus vaccine, which is an oral vaccine and will probably be administered at the same time as polio at two, four and six months. Both rotavirus and varicella are licenced in the US and are currently in the routine infant schedule in the US. (Rotavirus vaccine was temporarily suspended from the US schedule shortly after this talk, based on early surveillance reports of intussusception among some infants who received rotavirus vaccine. The Center for Disease Control and health departments will be collecting additional data in the next few months that may indicate more clearly whether the vaccine increases the risk of intussusception.~ Ed.)
A new immunisation handbook will be available from early next year and the new schedule is going to incorporate hepatitis B. It is likely that what will be recommended is for every newborn to have a dose of hep B vaccine, not just newborns from high risk mothers. The combination hep B and acellular pertussis will be given at two, four and six months, together with an injected Hib vaccine and oral polio vaccine.
Q. How successful was the schools-based MMR campaign?
We have just finished the evaluation. It went rather better than expected. Around 85% of children nationally were vaccinated in schools in the 5-12 year old group and around 10% were vaccinated by what we call other providers. So that made it look as though 95-96% of school age children were vaccinated. Now you might think that is an overestimate. However let me reassure you that we also did a very large sero-survey before and after the vaccination program and that involved 3,000 people under the age of 18 before the campaign and 3,000 afterwards. And in the 5-12 age group the sero-positive for measles went from 85% to 95% after the campaign and in the pre-school age group from 82% to 89%. So there has been a massive impact of the MMR vaccination program on immunity in those age groups.
Now what is interesting is the infant age group. Only 66% in the under twos were immune post-campaign, which indicates a lot of kids are not getting their first vaccine on time. That’s a group that needs to be targeted because there is still a lot of measles around; it is mainly in the older age groups and as far as the high school age group is concerned they are not as well protected as the primary school age group because they were not targeted in the program and the sero-survey shows that about 91% of the high school age group is protected. That is a group where it is very important to establish they have in fact had two doses. And if they haven’t give them another one. And if you are unsure give them another one because you are not going to do any harm by giving them an extra dose.
Q. What about adverse reactions during the campaign?
Nationwide we had a committee appointed to review the reactions on a two weekly basis and in total there were less than 100 reactions reported. By far the majority were children who fainted and had a short syncopal fit. There were six anaphylactic reactions, one or two arthritis, almost always transient and almost always due to the rubella component. Long term follow up of arthritis and arthropathy which you get with rubella vaccine shows it does wax and wane, but over a period of 12 months it usually burns itself out completely. There is good data on that now and of course if you have rubella illness the incidence of arthropathy after rubella is far in excess of the incidence after the vaccination.
So there was surprisingly little. All six children who had anaphylaxis following vaccination were treated very promptly by the nurses and there were no serious complications related to it.
Now the anaphylaxis related to MMR vaccine is interesting and it looks as though it is not associated with egg allergy. And there is now good data to show that egg allergic children have no more risk of getting anaphylaxis after MMR vaccination than normal children. There has been a big study of 400 severely egg allergic children in the Melbourne Children’s Hospital who have been vaccinated with no problems with MMR. None of them needed to have adrenalin. It looks as though the reason people get reactions after MMR is related to the gelatine in the vaccine and that has been shown in a small group of children in the US and a rather larger group in Japan, so that is probably the precipitating factor.
Q. What is your approach to anti-immunisation arguments?
Well, the anti-immunisation lobby is very vocal and they have good media coverage. They have a good PR machine and endless websites and you could become engulfed by the anti-immunisation push. However, as part of the evaluation of the MMR program we did almost 3,000 phone interviews of parents throughout Australia and it was very clear that less than 2% of parents have any sort of anti-immunisation feelings or beliefs and it is in fact an extremely small part of the general community. And clearly it is not the reason for the proportion of children who are not up to date.
There’s no doubt it makes parents worried when they hear these arguments. It is important to hear those concerns and to try to reassure parents. They say things like: “In general, the disease index is no lower now than it was before vaccination, and if it is, it is because of better nutrition and housing,” and so on. I don't think there's any argument that we have better nutrition and better housing conditions than during the depression and Second World War but that's the not the reason we got rid of hib disease.
Hib disease was prevalent in this country five years ago. Despite our good nutrition and housing, once we introduced the vaccine we went from 600 cases a year down to less than 20 cases a year over a very short period.
The same thing applies with poliomyelitis. I was in school during the polio outbreaks of poliomyelitis of the 1950s and I saw my school friends developing it and in fact I think all the children in my class had poliomyelitis.
Once we started vaccinating in 1955 we went from something like 1000 deaths a year down to three deaths in a period of 18 months. And the same dramatic change occurred with tetanus: 1000 deaths a year in pre-WWII down to three death a year now. So we have to get it in perspective. There is no doubt that there is the prospect of having worlwide eradication of polio in the same way we have had the worldwide eradication of smallpox and it is all due to vaccination.
Now there is the question of side effects, of contaminants in vaccinations. There is a huge push to try and say that the tiny amounts of preservatives in vaccines are likely to be damaging and I think one just has to be objective about that. There are very tiny amounts of formalin in tetanus and diphtheria vaccination, very tiny amounts of mercury preservatives - something like 0.02 per cent of mercury in some but not all of the vaccinations - and those tiny amounts are probably not much more than a formula fed baby would get in the water supply used to make up the formula.
A lot of the anti-vaccination movement quotes data out of context, and quotes data which is very old or quotes it in a way that it is polarised towards the argument they wish to preserve. You have to be very upfront with parents and maintain the fact that no vaccination is 100% effective or 100% safe.
What always concerns me is that if the doctor says to a parent that the child needs penicillen or an antibiotic, the parent practically never asks what are the risks of penicillen. And yet we get this very big push about what are the risks of vaccination - they are infinitesimally small in comparison, even now, with the risks of diphtheria, tetanus and whooping cough and measles.
Q. How often do people need a booster dose of hep B?
People who were vaccinated as infants are not considered at the present time to need boosters, so if as an infant you had a full course of hepatitis B vaccine even if you come from high risk environment, at the moment we do not have any evidence that boosters are needed. That data comes from high risk countries such as Taiwan and China where children are continually exposed in high risk situations. It has been found that they had very prolonged protection. Now it has been found that it is quite different for the healthcare worker or the person who has been vaccinated as an adult. And that's where careful follow up is needed and we suggest that they're revaccinated every five years or tested and revaccinated. If your level is less than 100 international units three to five years after the vaccine, you require a booster and usually you respond very well.
Q. Is there any evidence to suggest that we're doing harm or overloading babies' immune system when we vaccinate against a large number of illnesses when they're so young?
There does not seem to be any evidence at all suggesting that. I was only looking last week at the immunisation schedule we were using in 1989, which of course did not include hib vaccination and thinking how much simpler it was in 1989 than it currently is or is going to be in the next couple of years. And if you think about it, the health of our children 10 years later in on the whole rather better than 10 or 20 years ago. And just from general principle, there is no problem related to a lot of vaccinations.
What you have got to remember is once the baby is out of the uterus, it is exposed to many, many organisms in the environment, hundreds if not thousands of different organisms immediately. And the five or six or nine or ten we vaccinate for is a tiny drop in the ocean of organisms that the baby is exposed to out of the uterus. They are just scare tactics, this business you can paralyse the immune system. The immune system is working from hour one to combat the organism that the child is being exposed to.
Q. Pneumococcal vaccine - Is it a reality and how effective is it?
Pneumococcal vaccine is very similar to the Hib vaccine story. The early Hib vaccines were unconjugated. We had never had an unconjugated vaccine licenced in Australia. Once the vaccines were conjugated they were able to be very effective in children under the age of two. We have had pnuemococcal vaccination in Australia, the 23-valent, for quite some time now, for probably more than 10 years, closer to 15 for the early ones and 15 years for the 23-valent. But those vaccines are only really effective in children over the age of two or in adult and teenagers.
But what has been able to be done with pneumococcal is to conjugate it in a similar way to Hib vaccine so that they now work in children under the age of two. There's been a very big trial done in one of the health maintenance organisations in California with a 7-valent and now an 11-valent conjugated pneumococcal vaccine and they have been highly effective. What has happened with meningitis in childhood is that it was almost 50 per cent due to Hib and about a third due to pneumococcal and another third due to meningococcus so now we have almost eliminated Hib we have still got that big slice of childhood meningitis that is due to pneumococcal.
We also have the otitis media due to pneumococcal and also the huge morbidity in ear disease among Aboriginal children with the pneumococcal. So these conjugated pneumococcal vaccines at this stage have been unbelievably, 100 per cent effective against invasive pneumococcal disease in the trials in California and they are close to being licensed in the US and again they will be on the three dose schedule at two, four and six months and they will have to be by separate injection for the moment, but I would think we are looking at about two years before those vaccines come into the market here. I don't know whether they'll go onto the routine schedule but I would think there will be a great push to make them available for the Aboriginal community.
This interview was published in GPSpeak in August and October 1999.
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