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WORLD HEALTH ORGANIZATION TECHNICAL REPORT SERIES. 1980; (651):1-19.This document reports the discussions of a Scientific Group on Vaccination Against Tuberculosis, cosponsored by the Indian Council of Medical Research and the World Health Organization (WHO), that met in 1980. The objectives of the meeting were to review research on Bacillus Calmete-Guerin (BCG) vaccination, assess the present state of knowledge, and determine how to advance this knowledge. Particular emphasis is placed in this document on the trial of BCG vaccines in South India. In this trial, the tuberculin sensitivity induced by BCG vaccination was highly satisfactory at 2 1/2 months but had waned sharply by 2 1/2 years and the 7 1/2-year follow up revealed a high incidence of tuberculous infection in the study population. It is suggested that the protective effect of BCG may depend on epidemiologic, environmental, and immunologic factors affecting both the host and the infective agent. Studies to test certain hypotheses (e.g., the immune response of the study population was unusual, the vaccines were inadequate, the south Indian variant of M tuberculosis acted as an attenuating immunizing agent, and mycobacteria other than M tuberculosis may have partially immunized the study population) are recommended. A detailed analysis should be made when results from the 10-year follow up of the south Indian study population are available.
WORLD HEALTH ORGANIZATION TECHNICAL REPORT SERIES. 1974; (552):1-40.This document represents the work of a World Health Organization (WHO) Expert Committee on Tuberculosis, which met in Geneva in 1973. Chapters in this volume focus on epidemiology, Bacillus Calmette-Guerin (BCG) vaccination, case finding and treatment, national tuberculosis programs, research, WHO activities in this field, and the activities of the International Union against Tuberculosis and voluntary groups. The Committee emphasized that tuberculosis still ranks among the world's major health problems, particularly in developing countries. Even in many developed countries, tuberculosis and its sequelae are a more important cause of death than all the other notifiable infectious diseases combined. The previous WHO report, issued in 1964, set forth the concept of a comprehensive tuberculosis control program on a national scale. The implementation of this approach has encountered many problems, including deficiencies in the health infrastructure of many countries (shortages of financial, material, and physical resources and a lack of trained manpower) and resistance to change. However, many countries have instituted comprehensive programs and tuberculosis control has become a widely applied community health activity. A priority will be control of pulmonary tuberculosis. The Committee stressed that national programs must be countrywide, permanent, adapted to the expressed demands of the population, and integrated in the community health structure. Steps involved in setting up such programs include planning and programming, selection of technical policies, implementation, and evaluation. Research priority areas identified by the Committee include epidemiology, bacteriology and immunology, immunization, chemotherpy, the systems analysis approach to tuberculosis control, and training methods and instructional materials.
CHILD SURVIVAL ACTION NEWS. 1988 Apr; (9):1-2.Present thinking regarding the control of neonatal tetanus (NT) suggests that the accepted protocol in the past, i.e., immunizing pregnant women with tetanus toxoid (TT) during antenatal care, is not sufficient in countries where antenatal care may be unavailable. Current control strategies, experts, and official World Health Organization (WHO) recommendations now indicate that efforts should reach beyond immunization of pregnant women and the training of traditional birth attendants in hygienic cord care practice to immunization of all women of childbearing age. Babies continue to die form NT because it is so difficult to reach women during pregnancy for immunization. Lack of commitment to expanding immunization programs as Who recommends stems in part from failure at both national and local levels to acknowledge the extent of the neonatal tetanus problem. NT is vastly underreported for several reasons: cultural practices often include the seclusion of women and their babies during the period after birth; people in developing countries have a fatalistic attitude because so many children die within the 1st year of life; newborns are rarely taken to health centers for treatment; health workers may fail to report NT for fear that their superiors will blame them for failure to immunize or for poor care of the umbilical cord; Western medicine and research has a curative rather than a preventive focus; and gathering information on NT by asking mothers to recall deaths of newborns with symptoms of NT is difficult because many women are ashamed or otherwise unwilling to report the event. The WHO believes that conventional reporting systems in developing countries identify only 2-4% of actual NT cases. Without sound documentation of the problem, it is difficult to gain financial and political commitment to eradicating NT. The VIII International Conference on Tetanus that occurred in Leningrad during 1987 outlined WHO's recommendation for a mixed strategy to control and eliminate tetanus: immunize all women of childbearing age, with special emphasis on pregnant women and women known to belong to high risk groups; assure hygienic delivery and umbilical care through training and supervision of birth attendants; and investigate cases to determine what action could have prevented them.
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.
BULLETIN OF THE PAN AMERICAN HEALTH ORGANIZATION. 1984; 18(2):188-92.Outbreaks of yellow fever in recent years in the Americas have prompted concern about the possible urbanization of jungle fever. Vaccination, using the 17D strain of yellow fever virus, provides an effective, practical method of large scale protection against the disease. Because yellow fever can reappear in certain areas after a 2-year dormancy period, some countries maintain routine vaccination programs in areas where jungle yellow fever is endemic. The size of the endemic area (approximately half of South America), transportation and communication difficulties, and the inability to ensure a reliable cold chain are problems facing these programs. In addition, the problem of reaching dispersed and isolated populations has been addressed by the use of mobile teams, radio monitoring, and educational methods. During yellow fever outbreaks, many countries institute massive vaccination campaigns, targeted at temporary workers and migrants. Because epidemics in South America may involve extensive areas, these campaigns may not effectively address the problem. The ped-o-jet injector method, used in Brazil and Colombia, should be used in outbreak situations, as it is effective for large-scale vaccination. Vaccine by needle, suggested for maintenance programs, should be administered to those above 1 year of age. An efficient monitoring method to avoid revaccination, and to assess immunity, should be developed. The 17D strain produces seroconversion in 95% of recipients, and most is prepared in Brazil and Colombia. But, problems with storage methods, instability in seed lots, and difficulties in large-scale production were identified in 1981 by the Pan American Health Organization and WHO. The group recommended modernization of current production techniques and further research to develop a vaccine that could be produced in cell cultures. Brazil and Colombia have acted on these recommendations, modernizing vaccine production and researching thermostabilizing media for yellow fever vaccine.
[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.
BULLETIN OF THE WORLD HEALTH ORGANIZATION. 1985; 63(2):241-8.The WHO memorandum outlines the present situation regarding pertussis vaccines, discusses ways to evaluate candidate vaccines, and identifies future research needs. Most existing whooping cough vaccines are whole-cell vaccines, combined with diphtheria and tetanus toxoid adsorbed on an aluminum or calcium carrier. As whole bacterial cells, they contain a complex array of at least 7 toxins and antigens, and display a narrow margin between potency and toxicity. The Japanese introduced an acellular vaccine, admittedly sometimes less potent, called the Precipitated Purified Pertussis Vaccine, in 1981. This material contains far less bacterial mass, notably less endotoxin, and consequently produces less fever, erythema and induration. WHO has not yet established minimum requirements for standardization; even the mouse potency assay may not be suitable. There are techniques, however, which will measure amounts of component antigens and toxicity. Conflicting results on assays of potency and immunogenicity will have to be resolved. Besides the obvious need for large clinical trials of defined vaccines, a whole range of research needs were suggested, from genetic studies of the organism to specific details of the host response. It is generally agreed that a less reactogenic and more effective pertussis vaccine is needed and feasible.
[Unpublished] 1985. 15 p.This paper reviews the development of the global Expanded Program on Immunization (EPI) initiative, reports on program progress since the 1984 EPI conference, and identifies actions needed to meet the goal of providing immunization services to all children of the world by 1990. The central EPI strategy to date has been to deliver immunization in consonance with other health services, particularly those aimed at mothers and children. The long-term goal of such efforts is to strengthen the health infrastructure so as to ensure the continuous provision of immunization and other primary health care services. Simply by reinforcing existing health services, a coverage level of 60-70% will be achieved in developing countries by 1990. If universal coverage is to be achieved, external funds will have to be provided to meet operational costs and train national managers. Acceleration of existing efforts constitutes the main EPI priority at present. Specific areas suggested for immediate action include provision of information about immunization at every health contact; a reduction in the drop-out rates between 1st and last immunization; increased attention to the control of measles, poliomyelitis, and neonatal tetanus; improved immunization services to the disadvantaged in urban areas; and, where appropriate, acceleration of the EPI through approaches such as national immunization days. Ongoing actions that need to be pursued include strengthening disease surveillance and outbreak control, reinforcing training and supervision, and pursuing applied research and development. Overall, management capacity within national programs remains the most severe constraint for the EPI.
[Experience with the expanded WHO program on immunization against tetanus] Opyt rasshirennoi programmy VOZ po immunizatsii protiv stolbniaka.
ZHURNAL MIKROBIOLOGII, EPIDEMIOLOGII I IMMUNOBIOLOGII. 1985 Nov; (11):97-103.According to (WHO) statistics, over 1 million infants in the developing countries die each year from tetanus. The estimated annual occurrence of tetanus in the 3rd World exceeds 2.5 million cases, including approximately 1.3 million newborn infants. In 1974, WHO began an expanded program for the systematic immunization of infants against tetanus and certain other diseases. The program uses 2 approaches for preventing tetanus: 1) immunization of infants under 1 year of age with the AKDS vaccine; and 2) immunization of pregnant women or, if possible, all women, with tetanus anatoxin. The 2nd approach is more effective, especially when 2 doses of tetanus anatoxin are administered within a minimum interval of 4 weeks. The anatoxin has no harmful effects on the fetus and can be used during any stage of pregnancy. The program strives to reduce infant mortality caused by tetanus to less than 1 case in 1000 by 1990, and to 0 by 2000. To attain these goals, systematic immunization should be combined with drastic improvements in delivery techniques and hygiene in developing countries. Specialized surveys indicate that initial steps toward implementation of the program resulted in a significant reduction of infant mortality caused by tetanus. Experience with the expanded WHO program shows that elimination of tetanus in infants is a realistic and attainable goal.
[Expanded Programme on Immunization: Global Advisory Group] Programme Elargi de Vaccination: Groupe consultatif mondial.
Weekly Epidemiological Record / Releve Epidemiologique Hebdomadaire. 1984 Mar 23; 59(12):85-9.In addition to the conclusions and recommendations reached at the 6th meeting of the Expanded Program on Immunization (EPI) Global Advisory Group and summarized in this report, the Group reviewed at length the status of the program in the Western Pacific Region and made a series of recommendations specifically directed to activities in the Region. Of particular significance for the operational progress of the global program are the recommendations concerning "Administration of EPI Vaccines," which were subsequently endorsed by the Precongress workshop on Immunization held before the XVIIth International Congress of Pediatrics in Manila in November 1983. These recommendations are not listed here. In his report to the World Health Assembly in 1982, the Director-General summarized the major problems which threaten the success of efforts to achieve the World Health Organization (WHO) goal of reducing morbidity and mortality by providing immunization for all children of the world by 1990. The 5-Point Action Program adopted at that time remains a relevant guide for countries and for WHO as they work to resolve those problems. The EPI is concerned about the prevention of the target diseases, not merely with the administration of vaccine. In addition to working toward increases in immunization coverage, the EPI must assure the strenghtening of surveillance systems so that the magnitude of the health problem represented by the target diseases is known at the community, district, regional, and national levels; immunization strategies are continuously adapted in order to reach groups at highest risk; and the target diseases are reduced to a minimum. The development of surveillance systems is one of the priorities in the development of effective primary health care services. Disease surveillance in its various forms should be used at all management levels for monitoring immunization programs performance and for measuring program impact. Specific recommendations regarding disease surveillance to be undertaken at global and regional levels and at the national level are listed. The results of more than 100 lameness surveys conducted in 25 developing countries confirm that paralytic poliomyelitis constitutes an important public health problem in any area in which the disease is endemic. In most programs, initial emphasis should be placed on the develpment of sentinel surveillance sites to monitor disease incidence trends. Some progress has been made in acting on the recommendations made at the meeting on the prevention of neonatal tetanus held in Lahore in 1982, but intensification of activities is required. In many developing countries, the surveillance and control of diphtheria must be improved. All aspects of progress and problems in the global program are reflected at least somewhere in the Western Pacific Region, and most of the findings and recommendations generally are valid beyond the regional boundaries.
[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.