Measles: tots without shots

5. October 2011

Smallpox epidemics are history. In order for measles to disappear in the same way, high vaccination rates are needed, which have up until now been prevented by vaccination skeptics and difficult access to young children in Africa and Asia. According to experts, a vaccination would then be ideal when children receive their first medical attention: at birth.

It is almost exactly half a year ago since, in a Munich hospital, a 26-year-old patient died of measles. A doctor and a nurse caught the disease, and consequently there was one more patient. Fortunately they all survived the infection without consequences.

Measles: Until now ineradicable

Had the World Health Organization achieved its goals, such an incident would not have happened, as measles was supposed to have been eradicated in Europe by 2010. But for this to happen, at least nineteen out of twenty parents would need to make sure their child gets vaccinated. The only country in Europe which achieves this figure is Finland. Germany, with a rate of around 80 percent, lags far behind.

In many children’s doctors’ offices, with their waiting rooms and whining offspring, there is hardly time for a lengthy conversation with parents who have doubts as to the safety of vaccines. Ever widespread is the view that it would be better for children’s immune system to endure the disease than for them to be protected by prior injection. The best time for such a conversation with critical parents would actually be a long time before the birth of the child.

A study in Colorado has made the consequences of refusing vaccination clear: There, unvaccinated children have a 23 times greater risk of contracting whooping cough, the “chances” of getting chickenpox are nine times higher than those of vaccinees. Six times as many children without vaccination were treated in hospitals for pneumococcal infection. Plus: Whoever has a disease such as measles also has an increased risk of pneumonia. And further: almost one case in every five-hundred always turns out to be fatal.

A booster at birth closes gaps in vaccination protection

When it’s such that in Europe and the U.S. the skepticism of a measles vaccination is already so great, it is then much more difficult to eradicate pathogens in less developed countries. All the same, the international “Measles Initiative” in August reported that about one billion children in 60 developing countries have been vaccinated and that the global death rate has declined over the last ten years by almost four-fifths. The biggest problem areas for the organisation, along with India, are the African states of Congo and Ethiopia.

How can one reach mothers and their children in time to educate and protect? Guzman Sanchez-Schmitz and Ofer Levy of Harvard University recently discussed in the journal Science Translational Medicine the opportunity to vaccinate children while they are already in the presence of health care: At birth. If it were possible to prepare the baby’s immune system, soon after birth, for encounters with pathogens, a multiple-month window of susceptibility could be closed off. When the mother’s antibodies are gone after several months, the baby is, until its first vaccination, without protection. If the disease-carrying neighbourhood, or even the families themselves have contact with the infants as vectors, the risk of infection is high.

Problems: low titer, unilateral immune response

There are currently only three vaccines approved for neonatal use. The vaccines for the Hepatitis B virus, the oral Poliovaccine and the well-known BCG for tuberculosis, the world’s most widely used vaccine of all time. Both Pertussis vaccine as well as vaccines against diphtheria / tetanus have delivered in studies so far only suboptimal antibody titers in new-born infants.

A major problem in developing such vaccines in newborns is the weak Th1 immune response. The advantage of this blockage in the reaction is probably to prevent a response to foreign antigens of the mother and thus an abortion through its own deeds. While the developing immune system can handle extracellular attackers quite well, it still needs a bit more time to mature in forming an appropriate response to intracellular threats. Perhaps this defect can however be corrected with suitable adjuvants.

Regional antigenic variation

Another important point that vaccine researchers need to consider are the regional differences in the composition of the pathogens. Vaccination against Haemophilus influenzae type B is very effective in Finland, but not in Alaska. The situation appears to be similar for vaccines against rota-and hepatitis B viruses. Especially in countries where the hepatitis virus is widespread, there are new genotypes currently evolving against which the current vaccine (against type A2) only gives very limited protection.

A vaccine development system based on the frequency of subtypes devours huge resources. Protection via personalised on-demand vaccines remains for the time being an unattainable wish. Ten billion dollars in development costs alone for new vaccines is an estimate from the Bill & Melinda Gates Foundation for the next ten years. With a ninety-percent coverage in the areas of distribution of the most significant pathogens, nearly eight million children could be saved, writes The Lancet editor Peter Horton in an editorial from a few weeks ago. If one on the other hand considers measles, at a cost of about a dollar per injection for vaccination, the loss due to illness and death is far more than compensated.

Rumors and uncertainty migrate rapidly

Politics and the media can contribute much so that the chances of success could increase and that polio, and quite possibly measles, could soon disappear. But this requires a coordinated joint strategy. In 79 countries with diphtheria/tetanus vaccine, a recent study came upon 29 different immunisation schemes. In the debate over the safety of vaccination against hepatitis B, the French government and the WHO have contradicted each other several years ago and in so doing have made the population feel more uncertain. Ultimately, after a ten-year absence, polio reestablished itself in Nigeria, because political strife prevented a mass vaccination in the north of the country. Finally, there emerged in all the media the work of Andrew Wakefield, who, having worked with incorrect data, created a correlation between the vaccine against measles/mumps/rubella and autism and bowel disease. Not until twelve years after the publication did The Lancet officially withdraw the work.

Education about the importance of early vaccination is more necessary than ever. Small interest groups have, via social media, the possibility to spread their theses in the very shortest time around the world. At the same time, in the case of vaccination, just “waiting” is dangerous. The British Medical Journal reported in 2010 that maternal protection against measles probably comes to an end much faster than it was expected. An investigation by the University of Antwerp revealed that, from six months of age, all children were unprotected, regardless of whether the immunity in the mother originated from a vaccine or from the disease itself. In Germany, doctors inoculate children at an age between 11 and 14 months, and that, even then, is only if the parents are willing to do something to favour the elimination of the disease.

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