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Cholera: ancient scourge on the rise. WHO announces global plan for cholera control. (25 April 1991).
WHO FEATURES. 1991 Apr; (154):1-3.Vibrio cholerae spreads quickly via contaminated water and food, especially in areas with a poor health and sanitation infrastructure. Its enterotoxin induces vomiting and huge amounts of watery diarrhea leading to severe dehydration. 80-90% of cholera victims during an epidemic can use oral rehydration salts. A cholera epidemic is now spreading through Latin America threatening 90-120 million people (started in January 1991), particularly those in urban slums and rural/mountainous areas. As of mid April 1991, there were more than 177,000 new reported cases in 12 countries and 78% of these cases and more than 1200 deaths were limited to 5 countries: Brazil, Chile, Colombia, Ecuador, and Peru, WHO's Global Cholera Control Task Force coordinates global cholera control efforts to prevent deaths in the short term and to support infrastructure development in the long term. Its members are specialists in disease surveillance, case management, water and sanitation, food safety, emergency intervention, and information and education. WHO's Director General is asking for the support of the international community in cholera control activities. These activities' costs are considerable. For example, Peru needs about US$ 60 million in 1992 to fulfill only the most immediate demands of rehabilitation and reconstruction of the infrastructure. Costs of infrastructure capital throughout Latin America is almost US$ 5 thousand million/year over the next 10 years. It is indeed an effective infrastructure which ultimately prevents cholera. Cholera is evidence of inadequate development, so to fight it, we must also fight underdevelopment and poverty.
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.
[The control of viral diseases in the developing countries with the use of existing vaccines] Borba s virusnymi bolezniami v razvivaiushchikhsia stranakh s pomoshchiu sushchestvuiushchikh vaktsin.
ZHURNAL MIKROBIOLOGII, EPIDEMIOLOGII I IMMUNOBIOLOGII. 1991 Sep; (9):77-82.In developing countries, every year about 70 million measles cases occur with 1.5 million deaths, over 200,000 children contract paralytic poliomyelitis, 50 million people get infected with viral B hepatitis causing over 1 million deaths, and several thousand people perish because of yellow fever according to WHO data. At the present time, there are 12 vaccines against viruses: vaccines against German measles and mumps in addition to the above. The universal immunization program (UIP) of WHO targets measles and polio. In 1989, a WHO resolution envisioned a 90% immunization coverage by the year 2000. Measles vaccination is recommended for children aged 9-23 months, since most children have maternal antibodies during the first 3-13 months of age. The Edmonston-Zagreb vaccine provided seroconversion of 92, 96, and 98% for 18 months vs. the 66, 76, and 91% rate of the Schwarz vaccine. In the US, measles incidence increased from 1497 cases in 1983 to 6382 cases in 1988 to over 14,000 cases in 1989, prompting second vaccination in children of school age. The highest incidence of polio was registered in Southeast Asia, although it declined from 1 case/100,000 population in 1975 to .5/100,000 in 1988. Oral poliomyelitis vaccine (OPV) provides protection: there is only 1 case/2.5 million vaccinations. Hepatitis B has infected over 2 billion people. About 300 million are carriers, with a prevalence of 20% in African, Asian, and Pacific region populations. Plasmatic and bioengineered recombinant vaccine type have been used in 30 million people. The first dose is given postnatally, the second at 1-2 months of age, and the 3rd at 1 year of age. Yellow fever vaccine was 50 years old in 1988, yet during 1986-1988 there were 5395 cases with 3172 deaths in Africa and South America. Vaccination provides 90-95% seroconversion, and periodic follow-up vaccinations under UIP could eradicate these infections and their etiologic agents.
In: Vaccines for fertility regulation: the assessment of their safety and efficacy. Proceedings of a Symposium on Assessing the Safety and Efficacy of Vaccines to Regulate Fertility, convened by the WHO Special Programme of Research, Development and Research Training in Human Reproduction, Geneva, June 1989, edited by G.L. Ada, P.D. Griffin. Cambridge, England, Cambridge University Press, 1991. 173-84. (Scientific Basis of Fertility Regulation)Biologicals specialists at WHO review quality assurance of vaccines at the national level for participants in a symposium on vaccines to regulate fertility. National control authorities (NCA) authorize a company to manufacture biological products only after it convinces the NCA that it will comply with good manufacturing practices (GMP) and WHO requirements for manufacturing establishments and control laboratories. Experts periodically inspect the facilities to assure that the company abides by GMP, WHO, and national regulations. NCA makes a decision to permit product use after successful evaluation for a set period of time (licensing). The manufacture must renew its license. Licensing involves a review of manufacturer's data on production methods and laboratory tests. The manufacturer does not need to conduct some tests for each production lot including data on characterization of banks of seeds (cells, bacteria, and viruses), details on production methods, and principal harmlessness of the product. The NCA also reviews test data from each production batch at the bulk level, at the final bulk and/or at the final product level, and at the final product level. Bulk level tests may include tests for neurovirulence and for the absence of virulent mycobacteria. Purity tests are carried out at the final bulk and/or at the final product level. Tests for potencies of live vaccines, the absence of contamination, and adjuvant content are final product level tests. Results of clinical studies on the safety and efficacy of the product also accompanies requests for licensing. After granting a license, the NCA must define release modalities (free release, partial free release, or release after the NCA has issued a release certificate). It must also operate a postmarketing surveillance system to prevent the unexpected from happening.
In: Vaccines for fertility regulation: the assessment of their safety and efficacy. Proceedings of a Symposium on Assessing the Safety and Efficacy of Vaccines to Regulate Fertility, convened by the WHO Special Programme of Research, Development and Research Training in Human Reproduction, Geneva, June 1989, edited by G.L. Ada, P.D. Griffin. Cambridge, England, Cambridge University Press, 1991. 247-50. (Scientific Basis of Fertility Regulation)The 3 human chorionic gonadotropin (hCG) vaccines have shown the most potential for stimulating antibody production, but clinical trials have not yet tested for fertility reduction. Antifertility vaccine research began 20 years ago and it has taken this long to et this far because investigators have had to deal with the interaction of 2 complex systems--the immune system and the endocrine system. An example of this complexity is that no one understands why exogenous whole hCG does not induce a booster effect in hCG immunized women. Antifertility vaccines require much more effort than conventional antidisease vaccines because they will probably be used more often and more extensively than other vaccines. WHO should coordinate the trials of the 3 different vaccines to assure that researchers can designate the optimum preparation for particular cases. Other research indicates that cells and cell products may be vaccine candidates. Researchers may even try immunizing against other hormones beside hCG, gametes or their products, or the trophoblast. They may soon develop a T-cell vaccine which would be against the trophoblast. They speculate that eventually a composite vaccine will emerge which would have several targets therefore providing effective contraception and minimizing the immunological activity needed from each individual component. Biotechnology has allowed researchers to screen for many proteins such as those on the surface of spermatozoa which it can produce in great numbers. It may even be able to also screen for and manufacture carbohydrates making the zona pellucida to be a vaccine target. Potential areas of conflict once a vaccine is available are issues of ethics, national priorities, foreseeable abuse, and balance between individual rights and needs of future generations. Already contrasting points of view exist about an antifertility vaccine. Nevertheless the gravity of the demographic crisis calls for effective family planning technologies.
Perspectives on rapid elimination and ultimate global eradication of paralytic poliomyelitis caused by polioviruses.
EUROPEAN JOURNAL OF EPIDEMIOLOGY. 1991 Mar; 7(2):95-120.Paralytic poliomyelitis caused by the poliovirus has been almost completely eradicated in many countries. This was achieved by a maximal break in the chain of transmission through mass vaccinations. Strategies in the poor subtropical and tropical climates of Asia and Africa where annual estimates of paralysis are 250,000 cases must be adapted to countries characterized as having year-round fecal born infectious agents, including paralyzing polioviruses and other enteric viruses, and inadequate health facilities, poor sanitation and hygiene, and high levels of poverty. A virologic study in Mexico City and the Soviet experience lead to the successful Cuban strategy in 1962 of 2 annual, national days (2 months apart) of mass administration of OPV to all children in a specified age group, regardless of how many doses of OPV already had been received. The implementation by independently organized well-trained nonprofessional community volunteers is provided in detail. It is this strategy that is recommended for a WHO EPI group and Pan American Health Organization effort to eradicate poliomyelitis worldwide. The discussion of the worldwide effort to eradicate smallpox points out that the methods, used for smallpox eradication would be ineffective because poliomyelitis infections are clinically inapparent and vaccination around recognized cases is insufficient to break the chain of transmission. Problems arise due to the misdiagnosis of acute paralytic diseases which pathologically are not poliomyelitis. The distinction between paralytic poliomyelitis caused by polioviruses and paralytic poliomyelitis is made and discussed. The experiences of eradicating paralytic poliomyelitis in economically developed, temperate climate countries and rapid elimination in underdeveloped subtropical and tropical countries is described in some detail. The OPV programs and lessons learned in Cuba (1962), Brazil (1980), the Dominican Republic (1983), Nicaragua (1981), Paraguay (1985), and Mexico (1986) are included. Inadequate mass campaigns which did not work to break the chain of wild polioviruses but reduced the disease level were Columbia (1984), El Salvador (1985), and Turkey (1985). Measures of achievement in Latin American are identified, and recommendations for worldwide eradication are given.
The WHO Task Force on Vaccines for Fertility Regulation. Its formation, objectives and research activities.
HUMAN REPRODUCTION. 1991 Jan; 6(1):166-72.The WHO Task Force on Vaccines for Fertility Regulation is one of several Task Forces, consisting of international, multidisciplinary groups of scientists and clinicians collaborating in research on specific goals, established in 1972. Its accomplishments are reviewed here. The Task Force convened a meeting in 1974 to select criteria for tissues and molecules capable of mounting antifertility responses. These molecules had to be restricted to the target tissue, sequestered in the reproductive tract, present transiently, and chemically characterized. Some of the antigens considered were sperm enzymes and membranes, as well as a data bank of sera naturally immunized against sperm. Other were anti-ovum and placenta molecules such as zona pellucida, the SP-1 placental antigen, and the placental hormones chorionic somatotrophin and human chorionic gonadotropin (hCH). Trophoblast-derived monoclonal antibodies and gene libraries are being screened. Anti-hCH is the vaccine composed of a portion of the beta subunit complexed to a carrier antigen, diphtheria toxoid, in a water- oil emulsion with an adjuvant has been tested in a phase I clinical trial in 1986-1988. A Phase II trial is being planned to see if the immune response in women is large enough to be capable of preventing pregnancy. Further improvements in the vaccine are being envisioned, such as incorporation of the peptide carrier conjugate and immune stimulant into biodegradable microspheres, hopefully to produce a longer-lasting immunity and a more stable vaccine. While the WHO Task Force on Vaccines for Fertility Regulation has been forced to cut back on some avenues of research, its success has stimulated other centers to take up several important projects, e.g. the sperm LDH and zona pellucida vaccines.
SCIENCE. 1991 Mar 15; 251:1312-3.AIDS scientists met in February 1991 to discuss international trials of AIDS vaccines because of the urgency in conducting such trials since the US Food and Drug Administration approved 6 vaccines for trails. Major problems discussed were how to insure access to potential AIDS vaccines to developing countries, where to conduct future tests of vaccine efficacy, and which of the leading institutions should coordinate such an effort. The most difficult issue centered around who assumes the risks and who benefits. Many researchers considered conducting AIDS vaccine trials in developing countries since they have a large population varied in age and gender at high risk of HIV infection. Assuming an HIV vaccine is effective, additional questions must be addressed: How can a developing country afford a vaccine at free market prices? If that country does get the vaccine should not other developing countries also get it? Who will pay for it and distribute it? WHO has already contacted ministries of health about AIDS trials. Other organizations, e.g., the US Centers for Disease Control and the US National Institutes of Health, also already involved in international AIDS vaccine research do not want to be kept out of the Phase III trials. Some recommended that WHO be the international umbrella, others suggested that no organization control all the research. Nevertheless the vaccine will be produced in a rich country, and if left to the free market, it will be too expensive. 1 suggestions is a 2-tiered pricing plan in which rich countries pay higher prices thereby subsidizing the price in poor countries. Another is a patent exchange where the vaccine developers donate the vaccine patent to an international organization and they in turn can get an extension on an existing patent. Another alternative includes removing AIDS vaccines from the private sector altogether.