Showing papers on "Vaccination published in 1988"

Expanded programme on immunization.

Abstract: The Expanded Programme on Immunization (EPI) was established in 1974 to develop and expand immunization programmes throughout the world. In 1977, the goal was set to make immunization against diphtheria, pertussis, tetanus, poliomyelitis, measles and tuberculosis available to every child in the world by 1990. Problems encountered by the Programme have included: lack of public and governmental awareness of the scope and seriousness of the target diseases; ineffective programme management; inadequate equipment and skills for vaccine storage and handling; and insufficient means for monitoring programme impact as reflected by increasing immunization coverage levels and decreasing incidence of the target diseases. When the EPI was initiated in 1974, fewer than 5% of children in developing countries were receiving a third dose of DPT and poliomyelitis vaccines in their first year of life. These coverage levels have now surpassed 50% in developing countries, and millions of cases of the target disease have been prevented. Over 700,000 measles deaths were prevented by immunization in developing countries in 1987, and an increasing number of neonatal tetanus deaths is now being prevented by maternal immunization and improved childbirth conditions. Poliomyelitis immunization efforts have been so successful that the Pan American Health Organization is leading a drive to eradicate poliomyelitis from the Americas by 1990. The successes of the Programme represent a major public health achievement, but much remains to be done.(ABSTRACT TRUNCATED AT 250 WORDS)

The Transmission Potential of Monkeypox Virus in Human Populations

Abstract: Data on monkeypox in Zaire over the five years 1980-1984 are analysed to assess the protection imparted by past smallpox vaccination and the transmission potential of the virus in unvaccinated communities. Attack rates in individuals with and without vaccination scars indicated that smallpox vaccination (discontinued in 1980) imparted approximately 85% protection against monkeypox. It is predicted that monkeypox virus will continue to be introduced into human communities from animal sources, and that the average magnitude and duration of monkeypox epidemics will increase as vaccine-derived protection declines in the population. On the other hand, current evidence indicates that the virus is appreciably less transmissible than was smallpox, and that it will not persist in human communities, even in the total absence of vaccination. The findings thus support the recommendation of the Global Commission for the Certification of Smallpox Eradication to cease routine smallpox vaccination in monkeypox endemic areas, but to encourage continued epidemiological surveillance.

Protection against Japanese Encephalitis by Inactivated Vaccines

Abstract: Encephalitis caused by Japanese encephalitis virus occurs in annual epidemics throughout Asia, making it the principal cause of epidemic viral encephalitis in the world. No currently available vaccine has demonstrated efficacy in preventing this disease in a controlled trial. We performed a placebo-controlled, blinded, randomized trial in a northern Thai province, with two doses of monovalent (Nakayama strain) or bivalent (Nakayama plus Beijing strains) inactivated, purified Japanese encephalitis vaccine made from whole virus derived from mouse brain. We examined the effect of these vaccines on the incidence and severity of Japanese encephalitis and dengue hemorrhagic fever, a disease caused by a closely related flavivirus. Between November 1984 and March 1985, 65,224 children received two doses of monovalent Japanese encephalitis vaccine (n = 21,628), bivalent Japanese encephalitis vaccine (n = 22,080), or tetanus toxoid placebo (n = 21,516), with only minor side effects. The cumulative attack rate for encephalitis due to Japanese encephalitis virus was 51 per 100,000 in the placebo group and 5 per 100,000 in each vaccine group. The efficacy in both vaccine groups combined was 91 percent (95 percent confidence interval, 70 to 97 percent). Attack rates for dengue hemorrhagic fever declined, but not significantly. The severity of cases of dengue was also reduced. We conclude that two doses of inactivated Japanese encephalitis vaccine, either monovalent or bivalent, protect against encephalitis due to Japanese encephalitis virus and may have a limited beneficial effect on the severity of dengue hemorrhagic fever.

Volunteer studies of deletion mutants of Vibrio cholerae O1 prepared by recombinant techniques.

Abstract: Vibrio cholerae O1 A-B- vaccine strain JBK 70 and A-B+ CVD 101 prepared by recombinant DNA techniques from pathogenic EI Tor Inaba N16961 and classical Ogawa 395, respectively, were fed to 38 volunteers in single doses of 10(4) to 10(10). Although severe diarrhea did not occur in any vaccine, more than one-half developed mild diarrhea. These attenuated strains colonized well and elicited prominent vibriocidal and antitoxic (CVD 101) antibody responses. Recipients of a single dose of JBK 70 were significantly protected when challenged with 10(6) wild-type N16961. Diarrhea occurred in 7 of 8 controls but in only 1 of 10 vaccines (P less than 0.003, 89% vaccine efficacy), demonstrating the potency of immune mechanisms that do not involve cholera antitoxin. Further derivatives were prepared to explore the pathogenesis of the residual diarrhea, considering that either intestinal colonization by the vaccine itself or accessory toxins might be responsible. CVD 102, an auxotrophic mutant of CVD 101, did not cause diarrhea but colonized poorly and elicited feeble immune responses. Derivatives of JBK 70 and CVD 101 (CVD 104 and 105) deleted of genes encoding the EI Tor hemolysin still caused mild diarrhea. Genetically engineered strains can be colonizing, highly immunogenic, and protective single-dose oral vaccines, but they must be further attenuated before they can be considered for use as public health tools.

The Clinical Effectiveness of Pneumococcal Vaccine in the Elderly

Abstract: The effectiveness of pneumococcal vaccine in the immunocompetent elderly remains controversial. We report the results of a multicenter, case-control study of 244 controls and 122 patients, aged 55 years and older, hospitalized during a 5-year period with pneumococcal bacteremia, meningitis, or other bacteriologically confirmed pneumococcal infection. Two controls per patient were matched on the basis of admission date, hospital records, and underlying diseases. All subjects were selected without knowledge of immunization status with pneumococcal vaccine, and were excluded if there was evidence for immunosuppression due to disease or iatrogenic causes. The clinical effectiveness of the vaccine was calculated to be 70% (95% confidence intervals [CI], 37% to 86%) in this population, based on a Mantel-Haenszel point estimate of the odds ratio of 0.30 (95% CI, 0.14% to 0.63%; P less than 0.005). The clinical effectiveness of pneumococcal vaccine in preventing pneumococcal infection in the immunocompetent elderly approximates the vaccine's effectiveness in the general immunocompetent population.

Immunization of Pregnant Women with a Polysaccharide Vaccine of Group B Streptococcus

Abstract: Immunization of pregnant women with a polysaccharide vaccine of group B streptococcus is a promising strategy for the prevention of perinatal infections caused by group B streptococci. To explore the feasibility of this strategy, we vaccinated 40 pregnant women at a mean gestation of 31 weeks with a single 50-microgram dose of the Type III capsular polysaccharide of group B streptococcus. The only adverse effect detected was a mild local reaction in nine women (22 percent). Of the 35 women with low or unprotective antibody levels before immunization (less than 2 micrograms per milliliter), 20 (57 percent) responded to the vaccine. The geometric mean antibody level rose from 1.3 to 7.1 micrograms per milliliter four weeks after vaccination (P less than 0.02), and these levels persisted at delivery and three months post partum. Sixty-two percent of the vaccine-induced immunoglobulin in the mothers was IgG, which readily crosses the placenta. Infant antibody levels in cord serum correlated directly with maternal antibody levels at delivery (r = 0.913, P less than 0.001). Of the 25 infants born to women who responded to the vaccine, 80 percent continued to have protective levels of antibody at one month of age and 64 percent had protective levels at three months. Serum samples from infants with greater than or equal to 2 micrograms of antibody to Type III group B streptococcus per milliliter uniformly promoted efficient opsonization, phagocytosis, and bacterial killing in vitro of Type III strains. This effect could be mediated exclusively by the alternative complement pathway. Although this vaccine with an overall response rate of 63 percent is not optimally immunogenic, we conclude that maternal immunization is feasible and can provide passive immunity against systemic infection with Type III group B streptococcus in the majority of newborns. Larger trials with better vaccines will be required to evaluate the safety and clinical effectiveness of this strategy.

Duration of effectiveness of pertussis vaccine: evidence from a 10 year community study

Abstract: A 10 year study of whooping cough in a discrete general practice community was performed to assess longitudinally the efficacy of pertussis vaccine from one to seven years after immunisation. Of the 436 cases of whooping cough over 10 years, 326 occurred in children aged 1-7 years. The rate of immunisation was known for each cohort of children born during each year, and the attack rate of whooping cough was thus calculated for those immunised and unimmunized. The attack rates were highest in those cohorts exposed to the epidemics of 1977-9, 1981-3, and 1985-7. The efficacy of the vaccine was calculated as a percentage as (attack rate in unimmunized group--attack rate in immunised group) x 100/attack rate in unimmunized group. It fell from 100% in the first year to 46% in the seventh, being 84% in the fourth and only 52% in the fifth. Thus the pertussis vaccine or its schedule of use does not seem to provide sufficient herd immunity to prevent outbreaks of whooping cough. Matters might be improved if vaccination against pertussis were included in the preschool immunisation programme.

Antibody to Human Immunodeficiency Virus (HIV) and Suboptimal Response to Hepatitis B Vaccination

Abstract: Study Objective:To analyze the relation between human immunodeficiency virus (HIV) infection and the antibody response to plasma-derived hepatitis B vaccine. Design:Open-label longitudinal...

A group specific anamnestic immune reaction against HIV-1 induced by a candidate vaccine against AIDS

Abstract: The first experimental immunization of humans against the AIDS retrovirus, HIV-1, was started in a series of HIV seronegative, healthy volunteers in November 1986. For the primary vaccination recombinant vaccinia virus (V25) expressing the complete gp160 env protein of the HTLV-IIIB strain of HIV-1 was introduced by scarification. This elicited a weak primary response which we subsequently attempted to enhance by additional immunizations (boosting), using four different immunization protocols. We report here that intravenous injection of paraformaldehyde-fixed autologous cells infected in vitro with V25 (individual D.Z.) gave the best results. This individual received second and third boosts of intramuscular gp160 derived from an HTLV-IIIB clone using the hybrid vaccinia virus/bacteriophage T7 expression system. An anamnestic humoral and cellular immune reaction was achieved for over one year after the original vaccination, with high levels of antibodies to the viral envelope, and neutralizing antibodies against divergent HIV-1 strains such as HTLV-IIIB and HTLV-IIIRF (also called HTLV-III HAT) after the first boost. In addition, group-specific cell-mediated immunity and cell-mediated cytotoxicity against infected T4 cells were obtained after the primary vaccine and enhanced by the boosts. Finally, skin tests showed both immediate and delayed hypersensitivity to gp160 in vivo. Although this protocol is not practical for a large scale vaccine trial, our results show for the first time that an immune state against HIV can be obtained in man.

Measles in developing countries. Part II. The predicted impact of mass vaccination

Abstract: A mathematical model is developed to mimic the transmission dynamics of the measles virus in communities in the developing world with high population growth rates and high case fatality rates. The model is used to compare the impacts of different mass vaccination programmes upon morbidity and mortality arising from infection by measles virus. Analyses identify three conclusions of practical significance to the design of optimal vaccination programmes. First, there is no single optimum age at which to vaccinate children for all urban and rural communities in developing countries. For a given community the best age at which to vaccinate depends critically on the age distribution of cases of infection prior to the introduction of control measures. Second, numerical studies predict that the introduction of mass vaccination will induce a temporary phase of very low incidence of infection before the system settles to a new pattern of recurrent epidemics. Mass vaccination acts to lengthen the inter-epidemic period in the post-vaccination period when compared with that prevailing prior to control. Third, numerical simulations suggest that two-phase and two-stage vaccination programmes are of less benefit than one-stage programmes (achieving comparable coverage) aimed at young children. The paper ends with a discussion of the needs for: improved programmes of data collection; monitoring of the impact of current vaccination programmes; and the development of models that take account of viral transmission dynamics, host demography and economic factors.

Immunization of Healthy Adults with Live Attenuated Varicella Vaccine

Abstract: Live attenuated varicella vaccine was administered to healthy varicella-susceptible adults. Of 187 adults immunized with the Oka strain of vaccine, seroconversion to varicella-zoster virus (VZV) occurred in 82% after one dose and in 94% after two doses. Adverse effects were unusual. After immunization, one subject developed mild zoster caused by wild-type virus. Twelve adults developed a mild breakthrough case of chickenpox after exposure to VZV. Protection after household exposure was observed in nine (56%) of 16; however, the illness in all seven patients with breakthrough illness was modified, with an average of only 24 vesicles. Subjects seropositive at household exposure were unlikely to develop a breakthrough illness. Approximately 25% of vaccinees who seroconverted lost detectable antibodies to VZV after vaccination, but even those who became seronegative were partially protected. Varicella vaccine offered significant protection against severe chickenpox in healthy adults.

BCG vaccination against tuberculosis and leprosy.

Abstract: Origine, utilisation et protection par le BCG. Le probleme de l'explication de la protection par le BCG reste insoluble mais de grande importance

Efficacy of a Mass Hepatitis B Vaccination Program in Taiwan: Studies on 3464 Infants of Hepatitis B Surface Antigen—Carrier Mothers

Abstract: To evaluate the efficacy of the mass hepatitis B vaccination program in Taiwan in interrupting perinatal hepatitis B virus transmission, 3464 randomly selected 18-month-old infant vaccinees born to hepatitis B surface antigen—carrier mothers were recruited from 9697 eligible infants during a six-month period of the program. They were divided into ten groups according to maternal infectivity and compliance with the vaccination schedule. Serum samples were tested for hepatitis B surface antigen, antibody to hepatitis B surface antigen, and antibody to hepatitis B core antigen. In 786 infants who had highly infectious mothers and who received hepatitis B immune globulin and vaccine on schedule, the protective efficacy was about 85%. The efficacy seemed to be slightly lower in those immunized off schedule. Overall, 11% of infants still carried hepatitis B surface antigen, and 81% of the infants had antibody to hepatitis B surface antigen that exceeded 10 mlU/mL in more than 90% of them. The geometric mean titers of antibody to hepatitis B surface antigen were more than 200 mlU/mL in every group of infants. We conclude that the mass vaccination program is efficacious in preventing perinatal hepatitis B virus transmission and the chronic carrier state; most infant vaccinees have adequate levels of protective antibody at 18 months of age. This program is extremely significant in the control of hepatitis B virus infection in Taiwan. ( JAMA 1988;260:2231-2235)

New Concepts in the Pathogenesis, Diagnosis and Control of Diseases Caused by the Bovine Viral Diarrhea Virus

Abstract: The new information on the pathogenesis and epidemiology of mucosal disease of cattle is reviewed. It is now known that clinical mucosal disease occurs only in cattle which were infected with a pestivirus in early gestation and were born with persistent viral infection and specific immunotolerance. These animals may be clinically normal at birth but may develop fatal mucosal disease, perhaps following superinfection with another pestivirus, usually between 6 and 24 months of age. They may also remain clinically normal indefinitely and breed successfully. The progeny from persistently infected females will similarly be persistently viremic, and maternal families of such animals may be established.Congenital defects may occur when infection of the fetus occurs in mid-gestation. Although fetuses may be infected in utero in late gestation, the infections do not persist, the fetuses develop antibodies, and they appear to suffer no ill-effects. Postnatal infection can result in subclinical disease (bovine viral diarrhea) with a normal immune response; the virus may also be responsible for enhanced susceptibility to other infections, diarrhea in newborn calves, and reproductive failure.Prevention of the economically important diseases caused by the virus is dependent upon the identification and elimination of persistently viremic animals, which are reservoirs of infection, and the vaccination of immunocompetent females at least three weeks before breeding. However, because of serotypic differences between strains, there is some doubt whether vaccination will reliably provide protection against the transplacental fetal infections that are important in the pathogenesis of this disease. There is no substantial evidence to warrant the vaccination of feedlot cattle.

Efficacy of sequential annual vaccination with inactivated influenza virus vaccine

Abstract: Inactivated influenza virus vaccine efficacy after annual revaccination has been reported to be less than that after first vaccination in boarding school children. We prospectively examined the immunogenicity and efficacy of this vaccine in healthy 30- to 60-year-old volunteers in Houston, Texas, over two epidemic seasons (1983-1985) encompassing outbreaks due to influenza A (H3N2 and H1N1) and influenza B viruses. A placebo group that had never (or not in recent years) received inactivated influenza virus vaccine, a group that received the vaccine for the first time (first vac), and a group given two or more recent vaccinations (multivac) were evaluated in a double-blind fashion each year. Vaccination induced higher frequencies of rise in serum antibody titer to vaccine components in first vac than in multivac volunteers, but mean postvaccination titers were similar. Clinical and virologic evaluations of illnesses during both epidemics and of influenza infections diagnosed serologically over the epidemic seasons revealed no overall reduction in illness from that in the placebo group for either vaccine group; modest reductions in influenza infection-related illness that were significant only for the multivac group against A/H3N2-related illness (55%; p less than 0.04); reduction in moderate-to-severe lower respiratory and/or systemic illness due to influenza for multivac (73%, p less than 0.025) but not first vac (15%, p greater than 0.10) volunteers during the A/H3N2 epidemic; reduction in influenza virus shedding in the multivac (54%, p less than 0.05) but not the first vac (16%, p greater than 0.10) group when compared with the placebo group for both years; and overall 63-81% reductions in documented infections with each influenza virus for both vaccine groups with the exception of A/H1N1 for the first vac group (24%, p greater than 0.10) and type B for the multivac group (58%, p = 0.067). Vaccine efficacy was only modest in these studies, but in contrast to the earlier report in boarding school children, efficacy appeared to be somewhat greater after repeated annual vaccination than after first administration.

Immunization with a vaccinia virus recombinant expressing herpes simplex virus type 1 glycoprotein D: long-term protection and effect of revaccination.

Abstract: Previously we showed that mice immunized with a vaccinia virus vector expressing the herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) gene (vaccinia/gD) were protected against both lethal and latent infections with HSV-1 for at least 6 weeks after immunization (K. J. Cremer, M. Mackett, C. Wohlenberg, A. L. Notkins, and B. Moss, Science 228:737-740, 1985). In the experiments described here, we examined long-term immunity to HSV following vaccinia/gD vaccination, the effect of revaccination with vaccinia/gD, and the impact of previous immunity to vaccinia virus on immunization with the gD recombinant. Mice immunized with vaccinia/gD showed 100, 100, and 80% protection against lethal infection with HSV-1 at 18, 44, and 60 weeks postimmunization, respectively. Protection against latent trigeminal ganglionic infection was 70, 50, and 31% at 6, 41, and 60 weeks postvaccination, respectively. To study the effect of reimmunization on antibody levels, mice vaccinated with vaccinia/gD were given a second immunization (booster dose) 3 months after the first. These mice developed a 10-fold increase in neutralizing-antibody titer (221 to 2,934) and demonstrated a significant increase in protection against lethal HSV-1 challenge compared with animals that received only one dose of vaccinia/gD. To determine whether preexisting immunity to vaccinia virus inhibited the response to vaccination with vaccinia/gD virus, mice were immunized with a recombinant vaccinia virus vector expressing antigens from either influenza A or hepatitis B virus and were then immunized (2 to 3 months later) with vaccinia/gD. These mice showed reduced titers of neutralizing antibody to HSV-1 and decreased protection against both lethal and latent infections with HSV-1 compared with animals vaccinated only with vaccinia/gD. We conclude that vaccination with vaccinia/gD produces immunity against HSV-1 that lasts over 1 year and that this immunity can be increased by a booster but that prior immunization with a vaccinia recombinant virus expressing a non-HSV gene reduces the levels of neutralizing antibody and protective immunity against HSV-1 challenge.

Postmarketing surveillance for neurologic adverse events reported after hepatitis b vaccination experience of the first three years

Abstract: In 1982, the Centers for Disease Control, the Food and Drug Administration, and the manufacturer created a surveillance system to monitor spontaneous reports of adverse events occurring after inoculation with the new plasma-derived hepatitis B vaccine (Heptavax-B, Merck Sharp and Dohme, West Point, PA). In the three years between June 1, 1982 and May 31, 1985, an estimated 850,000 persons received the vaccine. During that period, a total of 41 reports were received for one of the following neurologic adverse events: convulsions (five cases), Bell's palsy (10 cases), Guillain-Barre syndrome (nine cases), lumbar radiculopathy (five cases), brachial plexus neuropathy (three cases), optic neuritis (five cases), and transverse myelitis (four cases). Half of these occurred after the first of three required vaccine doses. There were no deaths. Calculation of the relative risks of these illnesses after hepatitis B vaccination was highly dependent on diagnostic classification of the cases, estimates of the size of the vaccinated population, background incidence of the diseases, and the length and distribution of the hypothetical at-risk interval used in the analysis. Other factors important in judging the results of the study could not be measured, including underreporting. In some analyses, Guillain-Barre syndrome was reported significantly more often than expected (p less than 0.05, Poisson probability distribution). However, no conclusive epidemiologic association could be made between any neurologic adverse event and the vaccine. Even if such an association did exist, the preventive benefits of the vaccine in persons at high risk for hepatitis B would unequivocally outweigh the risk of any neurologic adverse event.

Malnutrition and overcrowding/intensive exposure in severe measles infection: review of community studies.

Abstract: Most hospital studies of measles mortality suggest that high case-fatality ratios are associated with malnutrition. However, no community study has documented this association. On the contrary, several community studies from Africa and Asia have found no relation between nutritional status and risk of severe or fatal measles. Instead, overcrowding and intensive exposure may be more important determinants of measles mortality. Clustering of several cases in the family and/or intensive exposure were associated with high measles mortality in community studies in West Africa, Bangladesh, and England. Thus sociocultural factors that concentrate many susceptible children in the home may increase the case-fatality ratio in measles. Conversely, this ratio will be lower when measles cases are dispersed. Siblings in rural areas, where long intervals separate epidemics, run a higher risk of contracting measles simultaneously than do their urban counterparts. Measles vaccination increases herd immunity and diminishes the clustering of several cases in a family. Vaccination may therefore reduce mortality even among unvaccinated children who contract measles. Crowding and intensive exposure may partly explain regional and historical variations in measles mortality; community studies suggest that mortality is high when a high proportion of measles patients have secondary cases (acquired through exposure at home).

Association of Influenza Immunization With Reduction in Mortality in an Elderly Population: A Prospective Study

Abstract: • We prospectively studied the efficacy of influenza vaccine during an influenza A/Arizona/80 (H3N2) outbreak at the Jewish Home and Hospital for the Aged in New York in the winter season of 1982 to 1983. All patients had been offered influenza vaccine before the outbreak; 181 chose to be vaccinated and 124 refused vaccination but agreed to participate in the study. Among those with serologic evidence of influenza infection, respiratory illness was significantly more common in the unvaccinated group (six of 14 vs one of 22). The overall mortality was 13 (7.2%) of 181 in the vaccinated group and 22 (17.7%) of 124 in the control group. The vaccinated and the control groups were examined for comparability. A logistic regression analysis, which controlled for differences in sex and level of nursing care, indicated that the difference in mortality was still significant, with a summary odds ratio of 2.7. The relative risk of death in the unvaccinated group was comparable at 2.18. Influenza vaccine reduced the mortality by 59% in the vaccinated group compared with the control group. ( Arch Intern Med 1988;148:562-565)

The use of mathematical models in the epidemiological study of infectious diseases and in the design of mass immunization programmes.

Abstract: The relationship between the number of people vaccinated for an infectious disease and the resulting decrease in incidence of the disease is not straightforward and linear because many independent variables determine the course of infection. However these variables are quantifiable and can therefore by used to model the course of an infectious disease and impact of mass vaccination. Before one can construct a model one must know for any specific infectious disease the number of individuals in the community protected by maternally derived antibodies the number susceptible to infectious the number infected but not yet infectious (i.e. with latent infection) the number of infectious individuals and the number of recovered (i.e. immune) individuals. Compartmental models are sets of differential equations which describe the rates of flow of individuals between these categories. Several major epidemiologic concepts comprise the ingredients of the model: the net rate of infection (i.e. incidence) the per capita rate of infection the Force of Infection and the basic reproductive rate of infection. When a community attains a high level of vaccination coverage it is no longer necessary to vaccinate everyone because the herd immunity of the population protects the unvaccinated because it lowers the likelihood of their coming into contact with an infectious individual. Many infections that confer lasting immunity tend to have interepidemic periods when the number of susceptibles is too low to sustain an epidemic. Mass vacination programs reduce the net rate of transmission of the infective organism; they also increase the length of the interepidemic period. Many diseases primawrily associated with children have much more serious consequences in older people and the question arises as to at what point childhood immunization will successfully prevent the more dangerous incidence of the disease in older cohorts. Mathematical models of disease transmission enable one to predict the course of epidemics design mass vaccination programs and be guided as to what are the relevant data that should be collected.

Safety of a Live-Attenuated Japanese Encephalitis Virus Vaccine (SA14-14-2) for Children

Abstract: In a study begun in 1985, 1,026 children between the ages of 5 and 12 years, living in an area of low Japanese encephalitis (JE) infection, were vaccinated with live-attenuated JE vaccine, strain SA14-14-2 A group of 47 of the vaccinated children, 5-6 years of age, were examined for fever and other systemic reactions every other day for 2 weeks following vaccination None of these children had temperatures greater than 374 degrees C or other systemic reactions during the observation period No untoward reactions were reported in the remainder of the vaccinated group After immunization, seroconversion rates in seronegative children were 100% (GMT 353, n = 11), 100% (GMT 317, n = 12), and 833% (GMT 23, n = 10) in groups receiving vaccine diluted 1:3, 1:5, and 1:50, respectively These results indicate that the JE SA14-14-2 live-attenuated vaccine is immunogenic and safe for children

Vaccination of calves with leukotoxic culture supernatant from Pasteurella haemolytica.

Abstract: In three experiments subcutaneous vaccination of calves with adjuvanted bacteria-free leukotoxic culture supernatant from log phase cultures of Pasteurella haemolytica A1 (toxin 1) was shown to induce some protection against intrabronchial challenge with live P haemolytica A1 This toxin 1 vaccine was as effective as a whole cell bacterin in stimulating agglutinating antibody to P haemolytica Induction of leukotoxin neutralizing activity was variable; in some cases vaccination only primed the animal to produce an anamnestic response after challenge, whereas in other instances antitoxic activity increased in response to immunization Two doses of vaccine were shown to be more effective than a single immunization Vaccination with leukotoxic culture supernatant from the nonpathogenic P haemolytica serotype 11 was as effective as vaccination with toxin 1 in stimulating antitoxic activity but was not protective This implies that both serospecific agglutinating activity and an antitoxic response are needed for immunity

Oral Immunization of Wildlife Against Rabies: Concept and First Field Experiments

Abstract: ministered by the oral route was raised by North American scientists in the 1960s. Subsequently, several American and European teams tested different vaccine strains in the laboratory for efficacy and safety and studied vaccine stabilization, vaccine delivery systems, bait acceptance by wild animals, and bait distribution schemes. The first field trial of a cloned SAD (Street Alabama Dufferin) strain in baits designed to immunize foxes orally was conducted in an Alpine valley in Switzerland in 1978. A population containing *60% immune foxes at the valley entrance stopped the spread of the disease into untreated upper parts of the valley. The strategic use of oral vaccination of foxes in additional regions of Switzerland resulted in freedom from the zoonosis in four-fifths of the country. The control of dog rabies by immunization has been successful since effective vaccines for veterinary use became available and were applied in mass vaccination campaigns. In many parts of the world, however, rabies remains endemic in populations of wild mammals. The idea of vaccinating susceptible freeliving species suggests itself, but most early attempts at establishing herd immunities at a reasonable level in populations of wild carnivores failed [1]. Obvi

Field trial of rhesus rotavirus vaccine in infants.

Abstract: Orally administered rhesus rotavirus vaccine (RRV) was evaluated in a placebo-controlled study in 176 infants (ages 2 to 4 months). Eighty-eight infants received a dose of 10(4) plaque-forming units of the vaccine, and 88 received the placebo. RRV was well-tolerated but mildly reactogenic in the 10 days after vaccination. There were mild febrile reactions (greater than or equal to 38 degrees C rectally) in 40% of the vaccinees and in 16% of the placebo recipients (P = 0.001). More of the vaccinees had loose stools than did the placebo recipients (P less than 0.05). RRV was immunogenic and induced a 4-fold or greater rise in serum neutralizing antibody responses in 67% of the vaccinees; however, breast-fed infants were less likely to develop a seroresponse than infants who were not breast-fed. Despite the good immunogenicity of RRV the overall incidence of rotavirus-associated illnesses was similar between the vaccine and placebo recipients. The failure of RRV in Rochester may be related to the fact that the circulating rotaviruses were predominantly serotype 1 and RRV is a serotype 3 rotavirus. Because the serotypes of rotavirus that predominate may vary from year to year, a polyvalent preparation may be necessary to provide effective vaccination against rotaviruses.

Serologic response to oral polio vaccine and enhanced-potency inactivated polio vaccines.

Abstract: In a randomized, controlled trial carried out from November 1980 to July 1983 involving 1,114 infants in Baltimore City and in Baltimore and Prince George's counties, Maryland, the serologic response to three doses of two enhanced-potency inactivated polio vaccines was compared with the response to three doses of oral polio vaccine. The mean ages at vaccination were 2.2, 4.7, and 19.9 months, respectively, for the three doses. Seroconversion after the first dose varied from 35% to 84%, and it was higher after oral polio vaccine than after either of the enhanced-potency inactivated polio vaccines for polioviruses types 2 and 3. Approximately two and one-half and 16 months after the second dose, almost all inactivated polio vaccine recipients had antibodies against all three virus types (98-100%). Fewer oral polio vaccine recipients had detectable antibodies to type 1 (89-92%) and to type 3 (96%). After three doses of vaccine, all children had antibodies against types 2 and 3. Approximately 1% of the inactivated polio vaccine recipients and 3% of the oral polio vaccine recipients lacked antibody to type 1. One or two doses of oral polio vaccine stimulated higher reciprocal geometric mean antibody titers against type 2 poliovirus than did the inactivated polio vaccine. For the other two types, the results were mixed. The third dose of inactivated polio vaccine produced significant increases in the reciprocal geometric mean titers against each of the three poliovirus types and resulted in significantly higher reciprocal geometric mean titers after three doses of vaccine for recipients of inactivated polio vaccine than for recipients of oral polio vaccine.