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Evidence behind the WHO guidelines: hospital care for children: what is the aetiology of pneumonia in HIV-infected children in developing countries?
Journal of Tropical Pediatrics. 2009 Aug; 55(4):219-24.This clinical review discusses the most common cause of pneumonia in HIV-infected children--bacterial pathogens and includes recommendations for the management of pneumonia in HIV-infected children from World Health Organization (WHO).
BULLETIN OF THE WORLD HEALTH ORGANIZATION. 1991; 69(6):667-76.WHO's Programme for Control of Diarrheal Diseases (CDD) promoted and supported research the purpose of which is to develop and evaluate vaccines against diarrheal diseases, but it focused on diarrhea control. In 1991, the WHO/UNDP Programme for Vaccine Development (PVD) began coordinating diarrheal disease vaccine research, yet CDD remained actively involved in vaccine trials. In March 1991, CDD and PVD cosponsored a meeting to specify new research priorities toward vaccines against rotaviruses, Shigella, cholera, and enterotoxigenic Escherichia coli (ETEC) infections. Synopses of clinical trials on vaccines that have undergone clinical trials are presented. Different methods of developing vaccines against rotavirus included heterologous rotavirus adapted to tissue cultures, incorporating the VP7 surface protein of human rotaviruses into an animal rotavirus, and naturally attenuated. Live oral vaccines, different ways to immunize with oral encapsulated antigens, and a gycoconjugate approach comprised the Shigella vaccine research. There were many candidate Shigella vaccines which the meeting participants found to be promising and challenging. Cholera vaccines included killed and live oral vaccines. The results of a large field trial of cholera vaccines (killed whole cell/B subunit and whole cell culture) in Bangladesh revealed marked improvements over injected vaccines. A study of children in Indonesia showed promise for strain CVD-103HgR as a 1 dose, live oral vaccine against cholera. Adult volunteers who received milk immunoglobulin concentrate with antibodies against several colonization factor fimbriae (LT and O antigens) and then challenged experimentally with ETEC were 100% protected. WHO emphasized the need to develop both living and nonliving oral ETEC vaccines which will grant broad spectrum immunity to young children. Specific recommendations follow each section on the various vaccines and general recommendations are included.
Report of the European Region on Immunization Activities. (Global Advisory Group EPI, Alexandria, October 1984). WHO/Expanded Immunization Programme and the European Immunization Targets in the Framework of HFA 2000.
[Unpublished] 1984. Presented at the EPI Global Advisory Group Meeting, Alexandria, Egypt, 21-25 October 1984. 3 p. (EPI/GAG/84/WP.4)Current reported levels of morbidity and mortality from measles, poliomyelitis, diphtheria, tetanus, and tuberculosis in most countries in the European Region are at or near record low levels. However, several factors threaten successful achievement of the Expanded Program on Immunization (EPI) goal of making immunization services available to all the world's children by the year 2000, including changes in public attitudes as diseases pose less of a visible threat, declining acceptance rates for certain immunizations, variations in vaccines included in the EPI, and incomplete information on the incidence of diseases preventable by immunization and on vaccination coverage rates. To launch a more coordinated approach to the EPI goals, a 2nd Conference on Immunization Policies in Europe is scheduled to be held in Czechoslovakia. Its objectives are: 1) to review and analyze the current situation, including achievements and gaps, in immunization programs in individual countries and the European Region as a whole; 2) to determine the necessary actions to eliminate indigenous measles, poliomyelitis, neonatal tetanus, congenital rubella, and diphtheria; 3) to consider appropriate policies regarding the control by immunization of other diseases of public health importance; 4) to strengthen existing or establish additional systems for effective monitoring and surveillance; 5) to formulate actions necessary to improve national vaccine programs in order to achieve national and regional targets; 6) to reinforce the commitment of Member Countries to the goals and activities of the EPI; and 7) to define appropriate activities for the Regional Office for Europe of the World Health Organization to achieve coordinated action.
In: Health and disease in developing countries, edited by Kari S. Lankinen, Staffan Bergstrom, P. Helena Makela, Miikka Peltomaa. London, England, Macmillan Press, 1994. 135-46.In the early 1980s approximately 4.6 million children under 5 years old died from diarrheal diseases each year in developing countries, and the annual number of diarrheal episodes in this age group was above 1 billion. Rotavirus is the single most important causal agent of acute and profuse watery diarrhea characterized by vomiting and fever. The typical age for rotavirus diarrhea is between 6 and 11 months of age. Enterotoxigenic Escherichia coli (ETEC) are found in 10-50% of cases of acute diarrhea in developing countries. Enteropathogenic E. coli (EPEC) also cause diarrhea in developing countries, but only in the first months of life. Shigellosis commonly refers to dysentery, the clinical picture of which includes fever, abdominal cramps, and bloody diarrhea with frequent, small and mucoid stools. Both S. flexneri and S. dysenteriae 1 are important causes of dysentery in developing countries. Shigellosis is one of the few diarrheal infections in which antibiotics are indicated. The clinical symptoms of Salmonella sp. include fever, abdominal pains, headache, and cough, and clinical signs include coated tongue, splenomegaly, rales in lungs, and relative bradycardia. Typhoid fever is endemic in large parts of the world with an estimated death toll of 500,000-600,000 per year. An estimated 120,000 deaths are caused annually by Vibrio cholerae. Today most cases of cholera are manageable with oral rehydration therapy (ORT). In addition, antimicrobials are routinely given. Case management of acute diarrhea includes treatment of dehydration by oral rehydration solution (ORS). The physiological principles of ORT were established in the 1960s. The World Health Organization formula for ORT is suitable for the management of all types of dehydration. Antimicrobials should be discouraged in uncomplicated acute diarrhea. Several causes of persistent diarrhea have been proposed including: infection with enteroadherent E. coli, enteropathogenic E. coli and Cryptosporidium; and intolerance to foods.
ANALES ESPANOLES DE PEDIATRIA. 1992 Jun; 36 Suppl 48:189.New vaccine developments will reflect achievements of the World Health Organization's (WHO) Expanded Programme on Immunization (EPI), as well as resistance from the public toward increasing numbers of vaccines. WHO's EPI program has concentrated on tuberculosis, diphtheria, tetanus, whooping cough, polio, and measles. 35 countries are attempting to control hepatitis B with universal vaccination. Now some countries are also recommending vaccination against Haemophilus influenza, mumps, and rubella. The complexity of multiple injections has prompted new research on acellular vaccines for pertussis, hepatitis A and B, varicella, and malaria. Combined vaccines and new adjuvants are also targets of intense research. Vaccines are a priority, because they are among the most cost-effective of medical interventions.
Human immunodeficiency virus (HIV) infection codes and new codes for Kaposi's sarcoma. Official authorized addenda ICD-9-CM (revision no. 2). Effective October 1, 1991.
MMWR. MORBIDITY AND MORTALITY WEEKLY REPORT. 1991 Jul 26; 40(RR-9):1-19.The addenda for Volumes 1 and 2 of the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) were reported by the Collaborating Center for Classification of Diseases for North America at the National Center for Health Statistics. This was the second revision of these codes for the classification of HIV infection. THe addenda, effective October 1, 1991, replace the addendum containing codes for human immunodeficiency virus (HIV) infection that went into effect January 1, 1988. The structure of the classification, the codes within the classification, and the use of the codes remained the same. 3 basic modifications were accepted. A new 3-digit category was created for Kaposi's sarcoma; several new clinical conditions were added (acute or subacute endocarditis, microsporidiosis, acute or subacute myocarditis, bacterial and pneumococcal pneumonia, histiocytic or large cell lymphoma, secondary cardiomyopathy and nephritis and nephropathy); and several categories of HIV manifestations were expanded to include similar conditions (viral pneumonia, encephalitis, encephalomyelitis and myelitis). These modifications will improve the accuracy of reporting and allow public health officials, clinical researchers, and agencies which finance health care to monitor diagnoses of AIDS and other manifestations of HIV infection. HIV infection is divided into 3 categories: HIV infection with specified secondary infections or malignant neoplasms, or AIDS; HIV infection with other specified manifestations; and other HIV infections not classifiable above. AIDS is not synonymous with HIV infection or with such terms as pre-AIDS or AIDS-related complex. To use these codes correctly, the physician must provide complete information and state the relationship between HIV infection and other conditions.
In: Disease and mortality in Sub-Saharan Africa, edited by Richard G. Feachem, Dean T. Jamison. Oxford, England, Oxford University Press, 1991. 173-89.In Sub-Saharan Africa (SSA), 1% of all children die of neonatal tetanus, 9% of measles, 3% of tuberculosis (TB), and 4% of pertussis. Further, .6% acquire paralytic polio. 20% of the .6% who acquire diphtheria die. Even though vaccination can control these diseases, only 20% of children in SSA receive the complete course of vaccination against the 6 diseases targeted by WHO's Expanded Programme on Immunization (EPI). But high vaccine coverage is not always a cure-all. For example, in the Gambia coverage is high but high mortality levels persist. Of the EPI diseases, measles is the greatest threat since it kills 2 million people annually in developing countries. Measles related mortality is highest in the 9 months following the disease. Even though tetanus is a major cause of death in neonates, tetanus also kills adults such as those that work with the land. Further the tetanus vaccination is effective in adults, but no adult program operates in SSA. Trained midwives reduce neonatal tetanus mortality by 76.6% and vaccination of pregnant mothers with 2 doses of tetanus toxoid reduces mortality 93.3%. Lameness surveys in SSA countries show that, contrary to earlier beliefs, paralytic polio is quite common (range 0.7-13.2). Administration of the oral polio vaccine and improved sanitation are responsible for a real fall in polio cases in the Gambia, the Ivory Coast, and Cameroon. TB was introduced into SSA in the 19th century. It mainly occurs in adults. The estimated life long risk of developing smear positive TB in SSA is 63. The case fatality rate of pertussis in the 1st year of life is high (3.2) and infants do no acquire maternal immunity against it, so the best control measures are early vaccination and identifying secondary cases among young siblings. Of the EPI diseases, scientists know the least about diphtheria in SSA. Its case fatality rate is high (11-38%) yet it is treatable. Primary problems of adequate vaccination coverage for the EPI diseases are managerial problems rather than technological.
[Unpublished] 1987 Nov. , 19 p.Immunizations often involve injecting a needle into the skin and, if health personnel do not take appropriate precautions, they can transmit pathogens such as hepatitis B and HIV. The most difficult form of microbe to destroy is bacteria encased in spores, e.g. Clostridium tetani. The most common method in developing countries to disinfect immunization equipment is to boil them nonstop for 20 minutes. Based on some studies, key researchers believe that exposure to 100 degrees Celsius water for several minutes can actually destroy or inactivate essentially all vegetative bacteria, viruses, protozoa, yeasts, and molds. Yet there is no agreement on the amount of time and temperature needed to inactivate the hepatitis B virus since some evidence indicates that it is highly resistant to heat (60 minutes needed) whereas other evidence indicates it is not very resistant (2 minutes). Many researchers believe HIV can be inactivated at 80 degrees Celsius. Health workers must clean immunization equipment before boiling since organic materials and oils on the equipment prevent heat penetration and protect microbes. Further they should submerge all equipment at the same time and make sure that the water is at full boil continuously for the entire specified time. Indeed health workers in developing countries should adhere to the procedure listed in the WHO/EPI/UNICEF pamphlet entitled How to Boil Needles and Syringes Properly. Steam is by far the best method to sterilize immunization equipment, however. WHO/EPI is trying to introduce portable special pressure cookers which can attain a temperature of 121 degrees Celcius to act as autoclaves for needles and syringes. WHO/EPI and UNICEF are exploring disposable syringes as another means of preventing disease transmission. Researchers are also working on developing vaccines that do not require injection such as the oral polio vaccine.
SCIENTIFIC AMERICAN. 1988 Nov; 259(5):126-33.Despite the tremendous strides in global immunization in less developed countries (LDCs) in the last 25 years, much remains to be done and the momentum has slowed. Vaccination programs continue to prove that they are less expensive, easier to implement, and in some cases more effective than other public health programs. Therefore it is imperative to produce and deliver new or improved vaccines to LDCs to prevent many infectious diseases and save the lives of children. Yet economic and political obstacles impede the development of these vaccines, even though the scientific know-how already exists. Manufacturers of vaccines that have been around for a long time and used widely in developed nations have often sold these vaccines to international agencies, such as WHO, at production cost. They do this because they have already recouped research & development (R&D) costs. When it comes to R&D of new vaccines, however, manufacturers are generally unwilling to invest time and money into R&D since they may not recoup their costs and make a profit. International agencies do not have the money to pay the high prices charged by manufacturers. Instead of the public health community in LDCs deciding on the development of new vaccines, the decision is left almost entirely in the hands of a few institutes or commercial manufacturers in the developed world. Other than continuing with the status quo, however, possible solutions do exist. For example, the UN could create an institute to develop and manufacture its own vaccines. Another possibility is that R&D and production of vaccines for diseases prevalent in an LDC or region could take place within that specified area.
VACCINE. 1988 Oct; 6(5):393-8.In developing countries, where economic development is lacking and literacy rates are low, priority must be given to primary health care and to the establishmend of sustainable health care delivery systems. The World Health Organization's Expanded Program of Immunization was designed with the goal of immunizing all children against measles, pertussis, tetanus, poliomyelitis, tuberculosis, and diphtheria by 1990. A second function of the immunization program is to establish a health care delivery system. Today 50% of infants receive 3 doses of diptheria/pertussis/tetanus and polio vaccines, and 70% receive at least 1 dose. Measles kills 2 million children every year. The standard strain of attenuated vaccine is given at 9 months, and 1 dose protects 95% of children for life. Tetanus kills 800,000 infants every year. The vaccine must be refrigerated, and 2 doses are essential. Tuberculosis kills 2 million children under 5 every year. The attenuated BCG vaccine should be given at birth, and a single dose confers some protection. Diphtheria is most common among poor, urban children in termperate climates, and 3 doses of toxoid at monthly intervals are recommended. Poliomyelitis paralyzes 250,000 children a year. 4 doses of live attenuated Sabin vaccine are recommended. The vaccine is very sensitive to heat. Other vaccines in use or being developed include yellow fever, meningococcus, Japanese B encephalitis, rubella, hepatitis B, cholera, rotavirus, pneumonococcus, and Haemophilus influezae. 2 problems that confront the delivery of health services, including immunization, are lack of funds and lack of access to susceptible populations. Approaches to the lack of funds problem include fee for service, taxation, beter management of existing resources, reallocation of health resources, and increased funding from donor nations. Approaches to the problem of access include vaccination whenever children come into contact with a health facility for any reason, channeling by members of the community, involvement of traditional healers and birth attendants, outreach services, mass campaigns, pulse technics, and financial incentives.
Lancet. 1989 Feb 18; 1(8634):396.The World Health Organization (WHO) issued a consensus statement about AIDS and sexually transmitted diseases (STD) and partner notification for patients with HIV infection. Evidence that genital ulcer disease (GUD) is a risk factor and facilitator for HIV-1 infection in heterosexual people is strong, especially in developing countries. A few studies have shown an association of antibodies to herpes simplex virus type 2 (HSV-2) and Treponema pallidum (the chief cause of genital and anorectal ulcers in developing countries). A consistent relation between HIV-1 and HSV-2 and T. pallidum has been demonstrated in seroepidemiological studies. Data assessing the link between other STD pathogens and HIV-1 transmission are insufficient, but it is plausible that all STD pathogens that cause genital ulcers or inflammation are risk factors for increased susceptibility to HIV-1 infection. Investigating this possibility should be a research priority, as genital ulcer diseases intervention may help to prevent sexual transmission of HIV-1 infection. Partner notification programs, as part of a comprehensive AIDS prevention and control program, should be carefully designed. Because the notification procedure can cause individual and social harm and detract from other AIDS prevention and control activities, a careful assessment of medical, legal, logistic, social, and ethical issues needs to be made. Other variables, such as cost, local environment, and epidemiology need to be taken into account. Issues of patient referral, target populations, training of notification personnel, patient consent, diagnostic accuracy, and the logistics of notification need to be addressed. WHO suggests that the following criteria be monitored when assessing efficiency of partner notification activities: number of index persons; number of partners identified; number of partners notified and their seroprevalence; cost; satisfaction; compliance and acceptability; counseling and support; staff training; confidentiality; and adequacy of follow-up.
INFECTION CONTROL. 1984 Nov; 5(11):538-41.In 1978 the Ministry of Health and Social Welfare (MHSW) of Liberia launched the Expanded Program on Immunization (EPI) with the 5-year objective of establishing an 80% reduction in child mortality and morbidity from measles, polio, diphtheria, neonatal tetanus, pertussis, and tuberculosis. The program at first adopted a strategy of using 15 mobile units in 11 operational zones to deliver vaccinations throughout the country. However, by 1980, despite support from the Baptist World Alliance, the UN International Children's Emergency Fund (UNICEF), and the World Health Organization (WHO), it became evident that the mobile strategy was neither economically feasible nor practical. Therefore, with support from the US Agency for International Development (USAID), the EPI shifted to a strategy of integrating immunization activities into the existing network of state health facilities. After 5 years, in 1982, the Program was evaluated by a team from the MHSW, WHO, USAID, and the Centers for Disease Control. The evaluating team felt that the EPI's strategy was good, but its goals were not being achieved due to deficiencies in funding, clinic supervision, and rural community outreach, as well as shortages of kerosene and spare parts needs to keep the essential refrigerators in operating condition. Measles remains endemic; in the capital, Monrovia, only 9% of the children have been vaccinated against it. Immunization coverage is particularly low in the capital the countries. Other reasons for low vaccination coverage in Liberia are lack of community awareness of existing facilities and the importance of vaccination and lack of coordination at the community level to use the existing facilities efficiently. International assistance is still needed, especially to develop heat-stable vaccines, so that maintenance of refrigerators will not be necessary.
[Acquired immunodeficiency syndrome (AIDS): WHO meeting and consultation on the safety of blood and blood products] Syndrome d'immunodeficit acquis (SIDA): reunion et consultation de l'OMS sur la securite du sang et des produits sanguins.
Weekly Epidemiological Record / Releve Epidemiologique Hebdomadaire. 1986 May; 61(18):138-40.The World Health Organization (WHO) convened a meeting of experts on April 14-16, 1986, to review the available information on the safety of blood and blood products in relation to acquired immunodeficiency syndrome (AIDS). It was attended by over 100 participants from 34 countries and followed by a consultation which took into consideration previous recommendations, new information, and many different circumstances which exist regarding AIDS at the global level. This discussion reports the main conclusions and recommendations of the consultation. Tests to detect antibody to the AIDS virus now are available to assist in the elimination of potentially infectious units of blood and plasma, yet it is important to recognize that information and education remain crucial elements in any AIDS prevention program and that they continue to be relevant to the safety of blood and blood products. In that respect, measures to limit the transmission of LAV/HTLV-III by whatever means will be most effective in communities which are as well informed as possible about the disease, how it is transmitted, and how donors can assist in assuring a safe blood supply by being alert to donor suitability criteria. In some countries risk factors for AIDS have been identified in homosexual and bisexual men, intravenous drug abusers, and their sexual partners. Self-exclusion systems in which persons with risk factors refrain from giving blood, and blood screening programs for virus antibody have been effective in contributing to a safe blood supply. Experience also has shown that frequently when persons infected with the AIDS virus have donated blood, risk factors could later be identified, but many of those donors may not have recognized or acknowledged that they carried a risk. The value of specific screening and control measures which have been found useful in many developed countries should be assessed by other countries in the context of their overall health programs and the availability of human and material resources. Well-accepted general principles concerning the use of blood and blood products need to be emphasized since they can contribute to the control of AIDS. The most important principles are: strategies of health services such as improved antenatal care can reduce the demand for blood and should be encouraged; when appropriate and safer components and derivatives can be produced and are available, they are preferable to whole blood or plasma; and whole blood or plasma should be transfused only when medically justified. Decisions to institute laboratory screening of donors should be made with full awareness that there are several essential components of such a program. Information and education for donors about AIDS, its risk factors, and blood transmission is one of the basic considerations. Exclusion based on a current history of possible exposures to known risk factors as well as symptoms can help to reduce the number of infected donors.
DEVELOPMENT FORUM. 1987 Mar; 15(2):1, 6.The author presents arguments to refute what he considers alarmist, unsupported generalizations about the origin and soread of AIDS (acquired immune deficiency syndrome) in Africa. The first myth is that AIDS originated in Africa, after a green monkey bit a man. There is no concrete evidence to support this theory. Moreover, if it were true, AIDS would have been known for years; there would be effective herbal remedies and folk traditions about the danger of green monkey bites. The syndrome is so distinctive, for example the oral candidiasis and striking wasting disease, called "slim" disease, that it would have been recognized long ago. Finally, numbers of cases have peaked in America first, a few years ago, and are now beginning to surge in some areas of Africa. A second myth is that countries are not reporting cases out of embarrassment. The author claims that reports to the WHO show far more cases of AIDS in the U.S. and Europe, and even if the 1000 cases in Africa as of 1986 were 1000-fold underestimated, they would be nowhere near the 5 or 10 million often printed. The third myth, that AIDS is out of control in Africa, is unsupported when the efforts of countries like Uganda are considered. Uganda has an extensive media campaign, significant funds relegated to fighting AIDS, foreign experts called in, blood testing equipment on order and in use in 2 hospitals. AIDS is only a problem in a few urban areas.
[Expanded Programme on Immunization: stability of freeze dried measles vaccine] Programme Elargi de Vaccination: stabilite du vaccin antirougeoleux lyophilise.
Weekly Epidemiological Record / Releve Epidemiologique Hebdomadaire. 1981 Jun 12; 56(23):177-9.This report brings up to date those data summarized previously regarding the stability of freeze-dried measles vaccine and is based on information obtained from the London School of Hygiene and Tropical Medicine. The World Health Organization (WHO) intends to establish a requirement for the stability of freeze-dried measles vaccine, and a draft of such a requirement is represented along with an analysis of how such a requirement would influence WHO acceptance of the vaccine included in this report. A plaque assay method was used to determine the potency of measles vaccine which had been stored in a freeze-dried state at 37 degrees Centigrade for varying intervals. Vaccine containers were exposed at 37 degrees Centigrade in a water bath and duplicate samples transferred to -70 degrees Centigrade at intervals ranging from 1 to 28 days. The residual infectious virus was determined by the plaque assay method in parallel with vaccine that had not been incubated. The results from 16 patches produced by 9 manufacturers are summarized in a table, which includes recent data a well as the results from the previous report. 2 criteria of stability are included: the number of days required for the live virus titer to drop to an acceptable minimum level when stored at 37 degrees Centigrade (Criterion 1); and the loss of live virus titer when stored for 7 days at 37 degrees Centigrade (Criterion 2). Neither criterion is sufficient on its own. A quite unstable vaccine might still have the required potency after being stored for a week at 37 degrees Centigrade if the vaccine had a high virus titer initially. Yet, a product with satisfactory stability might still fail the potency requirement if its initial virus titer was borderline. A figure shows how the vaccines would be rated according to the proposed requirements. The proposed requirement for the stability of freeze-dried measles vaccine will be presented to the Expert Committee on Biological Standardization during its meeting in September 1981. If accepted, it would become effective by March 1982.
Bulletin of the Pan American Health Organization. 1983; 17(3):323.A World Health Organization (WHO) Consultative Group on Hepatitis met during July 1983 to draft a global program for viral hepatitis control. At this time, hepatitis viruses infects tens of millions of people every year. These viruses can be transmitted by the fecal-oral route, in blood or certain blood products, and through intimate personal contact. Of the various forms (heptitis A, hepatitis B, and hepatitis non-A, non-B) hepatitis B arouses particular concern because it can produce chronic liver disease and premature death. Currently, there are over 200 million persistent carriers of this virus, many of whom will die of chronic liver damage. Firm evidence recently shows a clear cause and effect relationship between infection with hepatitis B virus and primary liver cancer, a common cancer that claims hundreds of thousands of lives a year. The July meeting made recommendations to improve the situation. One of the most important recommendations was to strengthen national capabilities to control viral hepatitis. The group also reviewed available diagnosis and control methods and suggested areas where action by the WHO would be most effective. The group agreed that the availability of safe and effective vaccines against hepatitis B provides a unique opportunity to break the chain of transmission and to prevent acute and chronic liver disease, including primary liver cancer. There has been concern that the plasma-derived hepatitis B vaccines could contain transmissible agents that might be implicated in the acquired immune deficiency syndrome (AIDS). It was felt that much care needs to be taken in selecting plasma donors and in purifying the immunizing component of the vaccine, known as hepatitis B surface antigen, so as to ensure a very high degree of purity and freedom from all infectious agencts. No evidence exists at this time of AIDS transmission by any hepatitis B vaccine.
Bulletin of the Pan American Health Organization. 1983; 17(2):212.A World Health Organization (WHO) sponsored scientific meeting concludes that hepatitis B vaccine presents unique opportunities for preventing a common type of human cancer by vaccination. Should these prospects be realized, it would be the 1st time an important human cancer has been prevented in this way. The 5-day meeting, held in February 1983, brought together specialists in biostatistics, epidemiology, molecular biology, pathology, virology, and vaccine development and production from 16 countries. The topic at the meeting was liver cancer, one of the 10 most common cancers in the world and one of the most prevalent cancers in developing countries. The evidence for the implication of hepatitis B virus in the etiology of primary liver cancer is based upon epidemiologic and geographic observations of a strong association between hepatitis B infection and this form of cancer and also upon recent results of molecular biology studies showing integration of hepatitis B viral DNA into the host's genetic material. About 80% of all liver cancers are thought to occur as a result of infection with hepatitis B virus. Actual development of such cancers is believed to proceed through a series of intermediate stages, including establishment of a persistent infection with the virus, the hepatitis B carrier stage, and integration of the virus into the host genome. Worldwide, survival, and persistence of the hepatitis B virus depends on a huge reservoir of human carriers, estimated conservatively to number over 200 million. Prolonged "shedding" of the virus by a portion of these carriers and its transmission to others by various routes helps to account for the high incidence of the disease. In many parts of the world perinatal infection and infection in early life play a very important role in transmission and often lead to continuing infection. Feasibility studies conducted in recent years in several countries with 2 newly developed hepatitis B vaccines demonstrated that immunization of babies can prevent natural infection with hepatitis B virus and also can prevent development of a persistent hepatitis B infection. It seems an appropriate time to take international action to plan and initiate a number of field intervention trials with the new vaccines among populations known to have high prevalence of hepatitis B infection, the hepatitis C carrier state, and liver cancer.