Haemophilus influenzae

Haemophilus influenzae type B

Haemophilus influenzae type B bacteria that cause each year, according to estimates, about 3 million cases of serious illnesses and an estimated 386 000 deaths, mostly caused by meningitis and pneumonia. Most of the victims are, almost, of children under the age of five, and those most vulnerable to disease age group ranging between four months and 18 months.

And pneumonia in developing countries, where the vast majority of these deaths occur, mortality larger number of deaths from meningitis. However, the meningitis caused by Haemophilus influenzae is also a serious problem in those countries, accounting for mortality rates several times higher than those recorded in developed countries; as it leaves, 15 to 35% of survivors with permanent disabilities such as retardation mental or deafness. The bacterium Haemophilus influenzae does not cause influenza, contrary to what the term might suggest.
The problem of Haemophilus influenzae type B

Possible to prevent Haemophilus influenzae type B - have been available highly effective vaccines since the early nineties. Yet hundreds of thousands of children still die annually from this disease.

There are major obstacles to prevention of Haemophilus influenzae type B are the lack of information and funds. The information shortage is largely due to the difficulty of diagnosing the disease - is often what kills most of its victims without being recognized. The scarcity of funds, resulting from the high price of vaccine for the disease compared with other classic childhood vaccines - at the price of the vaccine at the bottom of the world's income, in 2005, seven times the price of vaccines against measles, polio, tuberculosis, diphtheria, tetanus and pertussis.

Those two factors put many developing countries in a difficult situation. They want evidence of the size of the Haemophilus influenzae type B and the resulting damage before considering the possibility of the inclusion of the expensive vaccine in their infant immunization programs. These countries may need also to external financing in the event they decide to provide the vaccine.

The WHO recommends that, in recognition of these obstacles, to provide vaccine for Haemophilus influenzae type B "when resources permit its use and the burden of disease." And included the efforts undertaken by the World Health Organization and other international health organizations, in recent times, the implementation of programs to help countries to identify the true burden of disease caused by Haemophilus influenzae type B, and to help them devise ways to get the vaccine for this disease.
The burden of Haemophilus influenzae type B vaccination in industrialized countries

I started the industrialized countries, thanks to sophisticated systems for surveillance of health, aware of the threat inherent in the Haemophilus influenzae type B, for fifty years. Turns out, before the start of immunization programs in the early nineties, that the disease is the main reason behind the bacterial meningitis that struck children in all countries which appropriate studies were performed almost, including Australia, Canada, Finland, the Netherlands, Sweden and the United States of America. (Not available on the rate of accurate pneumonia caused by Haemophilus influenzae type B, although it was considered to occur less often than meningitis - the opposite of what is prevalent in the developing world.) Was to get rid of the disease is almost entirely in the industrialized countries Systematic vaccination.
Current vaccine coverage

The 89 countries immunization of infants against Haemophilus influenzae type B in late 2004, while not providing two of those countries that immunization only in some of their territories. Have been vaccinated 92% of the population of developed countries against the disease as of 2003. The rate of vaccination coverage was 42% in developing countries and 8% in the least developed countries (mostly in sub-Saharan Africa). The incidence of Hib matter of discussion in South East Asia, the level of use of the vaccine for this disease is very low. In 2002, Malaysia began, the first Asian country to introduce the vaccine, the implementation of the program in the area of regular vaccination against Haemophilus influenzae.
A hidden disease

There are Haemophilus influenzae type B, generally in the noses and throats of healthy individuals living in areas that have not yet carried out a campaign of vaccination. And all unvaccinated children almost at risk of the disease when they reach the age of five. And spread the bacteria causing the disease by what comes out of the nose or throat spray. And can be implemented that invade the bloodstream and cause infection and disease in other parts of the body, including the meninges (membranes covering the brain and spinal cord) leading to meningitis, and the lungs, causing pneumonia.

And haemophilus influenzae type B does not cause, in contrast to measles and diphtheria, the disease can be identified separately. Among the most common form of infection caused by the deadly Hib pneumonia and meningitis, but it might be for these two diseases are other reasons, may look the same whether caused by Hib or one of the other factors. There are More rarely, Hib is responsible for other life-threatening complications of young children, such as septic arthritis, and septicemia or blood poisoning, which also can have other causes. And Hib can cause epiglottitis (an inflammation may die from it and get the flexible cartilage that covers the vocal cords during swallowing).

Doctors who are treating cases of pneumonia in children, usually, to respond quickly with antibiotics in order to save the lives of infected children. However, it must, to verify that the situation is really one of the cases of Haemophilus influenzae type B, the sampling of an ill person - taking a blood sample in the case of pneumonia, and taking a sample of cerebrospinal fluid by lumbar puncture in the case of meningitis - and must, then be isolated MRSA from those specimens in a laboratory. That is a challenge even for sophisticated laboratories. May not be made that laboratory tests in developing countries at all, or laboratories may fail to carry them out properly, or may not be able to such tests to detect bacteria because antibiotics were given before the sampling.

And often results in hidden nature by Haemophilus influenzae type B can not evaluate their effects. Studies have shown that there is a lack of awareness of this disease among medical professionals in some developing countries, or that they do not see the effects only in the Hib meningitis - with the frequency of cases of pneumonia caused when in fact the frequency of meningitis, five times in those countries. In 2004, the Global Alliance for Vaccines and Immunization that the burden of Haemophilus influenzae type B is "fraught with ambiguity."
Tools for assessing the incidence of Haemophilus influenzae type B

Studies have shown large-scale population-based disease burden that the rates of meningitis caused by Haemophilus influenzae type B, ranging from 20 to 60 cases per 100 000 children under the age of five in the United States of America (before the start of immunization); and 40 to 60 cases per 100 000 in sub-Saharan Africa; and 10 to 40 cases per 100 000 in Latin America and Western Europe.

Most studies from Asia and Eastern Europe, rates much lower rates - fewer than 10 cases per 100 000. However, there are studies based on the introduction of Hib vaccine has been given to residents of Lombok, Indonesia, and Dhaka, Bangladesh, led a team of experts of the World Health Organization to conclude in 2004 that "the incidence of cases of meningitis caused by Haemophilus influenzae type B was, in both studies, greater than could be measured through surveillance for laboratory-confirmed cases. " There is a tendency to use statistics on meningitis in studies of Haemophilus type B instead of using the statistics of pneumonia, so that the possibility of diagnosis of meningitis caused by Hib properly far outweigh the possibility of diagnosis of pneumonia caused by it.

Turns out, in recent times, that existing studies on the impact of vaccine of Haemophilus influenzae type B is an effective means to assess the burden of this disease. In these studies, vaccination of a population vaccine for the disease and compared the subsequent reductions in cases of meningitis and / or pneumonia with the numbers of cases registered prior to vaccination. Such studies have been carried out in Chile, Colombia, Gambia, Indonesia, Uruguay and other countries. In the Gambia, the proportion of annual cases of meningitis during the past 12 months, from more than 200 per 100 000 to 21 per 100 000, and the disease has now virtually disappeared. In Colombia, decreased the incidence of acute bacterial meningitis by 40% in one year.

A "Rapid Assessment Tool" by the World Health Organization and U.S. Centers for Disease Control and Prevention to help countries to assess the size of Haemophilus influenzae type B, through the study of past hospital or mortality rates or rates of deaths from meningitis. This tool has worked well in many areas, but the World Health Organization is currently considering, in order to reduce the differences in diagnostic patterns of disease in Eastern Europe and Asia, the possibility of adapting or revising this tool for use in those regions of the world.
Treatment

Is the treatment of Haemophilus influenzae type B by intensive treatment plans and an unbroken based on antibiotics, but those plans are not always available to people in developing countries.

Resistance of Hib to several antibiotics are effective in the least expensive is a growing concern of the factors that contribute to the impetus for expanding vaccine coverage.
Vaccination regime and cost

Is the conjugate vaccines, anti-Haemophilus influenzae type B, given by intramuscular injection, the vaccines are highly effective and do not result in almost no side effects. And is usually administered three doses in infancy, starting from the age of six weeks. And is also, in some countries, a booster dose between 12 months and 18 months of age, although this might not be necessary in countries where there is the occurrence of disease, such as African and Latin American countries. We are now, and increasingly, giving the vaccine in the context of combination vaccines which can also include protection against diphtheria, tetanus, pertussis, and hepatitis type B.

Currently, the price of vaccines against Haemophilus influenzae type B, as provided to developing countries, about U.S. $ 7 per child for the recommended three doses. (The strange thing is that the price of the full treatment plan for each of the six standard vaccines given to children in developing countries, measles, polio, diphtheria, pertussis, tetanus, and tuberculosis, was only about one dollar.)
The steps taken in order to provide the vaccine at affordable prices

Detect the Global Alliance for Vaccines and Immunization unveiled a strategy to expand coverage vaccines of Haemophilus influenzae type B in the poorest countries of the world's 75 countries, with emphasis on external funding and to ensure the sustainability of funding in these countries after five years, that is done, probably, through joint arrangements between governments and donors in the long term. GAVI in the month of May 2005, the Special Initiative against Haemophilus influenzae type B to a consortium including Johns Hopkins University, and the London School of Hygiene and Tropical Medicine, the Centers for Disease Control and Prevention, the World Health Organization. This initiative will provide countries with research and technical assistance necessary to address and clarify the possible inclusion of a vaccine against Hib.
What are the activities undertaken by the World Health Organization

In 1998, WHO noted that: "Haemophilus influenzae type B is, in all the sites was carried out extensive studies, one of the important reasons leading to the occurrence of meningitis in childhood and one of the main reasons behind the occurrence of bacterial pneumonia in children. Accordingly, it is necessary, in view of the safety of conjugate vaccines, countermeasures to this disease and efficacy of vaccine introduction of Hib, in accordance with national capacities and priorities, the programs of routine infant immunization. as it should, in geographic regions where the burden of disease is unclear, efforts to assess the size of this problem. "

World Health Organization from those actively involved in the initiative launched by the Global Alliance for Vaccines and Immunization against Haemophilus influenzae type B, which will help countries to consider whether the inclusion of the vaccine for Hib from a public health priority for her, In that case, consider how to introduce the vaccine in a sustainable manner.

Among the purposes identified by the vision and strategic wars in the area of immunization, which put them all from the World Health Organization, UNICEF and other partners, "Strengthening the current immunization system so that it can access the currently available vaccines and vaccines are not used adequately to the degree possible," including in the vaccine anti-Haemophilus influenzae type B. Include vision and strategy OIE also the objective of "the necessity of that half of the poorest countries, with high disease burdens heavy and have adequate systems for the delivery of health services, the introduction of vaccine for Haemophilus influenzae type B by the end of 2005."

World Health Organization