Showing papers on "Vaccination published in 1990"

Protection of chimpanzees from infection by HIV-1 after vaccination with recombinant glycoprotein gp120 but not gp160

Abstract: The development of a vaccine to provide protective immunity to human immunodeficiency virus type 1 (HIV-1), the virus causing AIDS, would be the most practical method to control its spread. Subunit vaccines consisting of virus envelope glycoproteins, produced by recombinant DNA technology, are effective in preventing viral infections. We have now used this approach in the development of a candidate AIDS vaccine. Chimpanzees were immunized with recombinant forms of the HIV-1 glycoproteins gp120 and gp160 produced in Chinese hamster ovary cells, and then challenged with HIV-1. The control and the two animals immunized with the gp160 variant became infected within 7 weeks of challenge. The two animals immunized with the gp120 variant have shown no signs of infection after more than 6 months. These studies demonstrate that recombinant gp120, formulated in an adjuvant approved for human use, can elicit protective immunity against a homologous strain of HIV-1.

A randomized, prospective field trial of a conjugate vaccine in the protection of infants and young children against invasive Haemophilus influenzae type b disease.

Abstract: Background. Haemophilus influenzae type b is the leading cause of invasive bacterial disease in young children. The capsular polysaccharide vaccine does not protect children at greatest risk (those under the age of 18 months), but a polysaccharide—protein conjugate vaccine has proved to be more immunogenic in this age group. Methods. We enrolled 114,000 infants in Finland in an open, prospective, randomized trial of a H. influenzae type b capsular polysaccharide—diphtheria toxoid conjugate vaccine (polyribosylribitol phosphate—diphtheria toxoid [PRP-D]). Children born on odd-numbered days were vaccinated at the ages of 3, 4, 6, and 14 to 18 months; those born on even-numbered days formed the control group and received the same vaccine at the age of 24 months. Results. After three doses of the vaccine there were 4 cases of verified bacteremic H. influenzae type b disease in the group receiving early vaccination, as compared with 64 cases in the control group, between the ages of approximately 7 an...

Ablation of eosinophil and IgE responses with anti-IL-5 or anti-IL-4 antibodies fails to affect immunity against Schistosoma mansoni in the mouse.

Abstract: To investigate the role of anaphylactic immune responses in protective immunity against schistosomiasis, mice vaccinated with irradiated cercariae of Schistosoma mansoni were treated with neutralizing mAb antibodies against either IL-5 or IL-4 before and during challenge infection. Anti-IL-5-treated vaccinated mice showed a complete ablation of circulating as well as tissue eosinophils present in inflammatory reactions to migrating schistosomula in the skin and lungs but nevertheless eliminated challenge infections as effectively as vaccinated animals treated with a control mAb. Similarly, treatment of vaccinated mice with an anti-IL-4 mAb markedly reduced serum IgE although failing to diminish immunity. The effect of anti-IL-5 mediated eosinophil depletion was also assessed in a second model in which resistance is induced by concomitant chronic infection. Again, normal, unaltered protection was observed in the absence of circulating and tissue eosinophils. In contrast to the above findings, treatment with anti-IFN-gamma was found to cause a partial depletion of immunity in vaccinated mice whereas, paradoxically, increasing the numbers of inflammatory reactions against invading schistosomula in the lungs. These observations argue against a requirement for either eosinophils or IgE in the anti-schistosome immunity induced by vaccination with irradiated cercariae or for eosinophils in the resistance resulting from previous infection in mice and support previous data suggesting a role for an IFN-gamma dependent cell-mediated effector mechanism in vaccine-induced resistance.

Pneumococcal Polysaccharide Vaccine in Young Adults and Older Bronchitics: Determination of IgG Responses by ELISA and the Effect of Adsorption of Serum with Non-Type-Specific Cell Wall Polysaccharide

Abstract: Available pneumococcal vaccines provide only limited protection for certain at-risk populations. Fifteen healthy young adults and 11 older chronic bronchitics received 23-valent pneumococcal vaccine. ELISA showed that IgG reactive with capsular polysaccharides from Streptococcus pneumoniae serotypes 3, 4, 8, 14, and 19F increased after vaccination. Bronchitics exhibited lesser responses for four of these serotypes, although differences between the groups were significant only for serotype 3. Adsorption of postvaccination sera with pneumococcal cell wall polysaccharide significantly reduced mean antibody levels in both groups and lowered the proportion of sera that demonstrated type-specific antibody responses. Reactive IgG was largely restricted to the IgG2 subclass. Pneumococcal vaccine may provide suboptimal protection of older adults because antibody responses to some capsular polysaccharides are lower in elderly bronchitics than in healthy young adults. A substantial proportion of measured antibody reflects IgG reactive with cell wall polysaccharides rather than with type-specific, capsular constituents, suggesting that antibody responses in subjects of all ages deserve reappraisal.

Frequency of Adverse Reactions to Influenza Vaccine in the Elderly: A Randomized, Placebo-Controlled Trial

Abstract: Concern about side effects constitutes a major deterrent to patient compliance with influenza vaccination, yet there is a paucity of data about the occurrence of adverse reactions in the population targeted for immunization. We conducted a randomized, double-blind, crossover trial to compare the frequency of adverse reactions following administration of 1988-1989 trivalent split-antigen influenza vaccine and saline placebo. Outpatient veterans 65 years of age or over (n = 336) were recruited by mail and were randomly assigned to receive vaccine followed 2 weeks later by placebo injection or placebo followed 2 weeks later by vaccine. There was no significant difference between influenza vaccine and placebo with respect to the proportion of subjects reporting disability or systemic symptoms. ( JAMA . 1990;264:1139-1141)

A Recombinant Human Adenovirus Vaccine against Rabies

Abstract: Rabies continues to be a serious problem in both developed and developing nations due to the reservoir of rabies virus in wildlife vectors. The control and worldwide eradication of rabies depends on the development of safe, effective, and economical vaccines that might be used in preexposure vaccination programs for humans and animals. To this end an infectious human adenovirus type 5 recombinant virus that contains the rabies glycoprotein gene, and which may serve as the prototype for a new class of vaccines against rabies, was constructed and tested. This recombinant, when administered by either the parenteral or oronasal route, was highly effective in eliciting good levels of rabies-neutralizing antibodies in the sera of dogs and mice. Mice immunized by the recombinant virus were protected from lethal intracerebral challenge with rabies virus.

Mild Measles and Secondary Vaccine Failure During a Sustained Outbreak in a Highly Vaccinated Population

Abstract: A prolonged school-based outbreak of measles provided an opportunity to study "vaccine-modified" mild measles and secondary vaccine failure. Thirty-six (97%) of 37 unvaccinated patients had rash illnesses that met the Centers for Disease Control clinical case definition of measles, but 29 (15%) of 198 vaccinated patients did not, primarily because of low-grade or absent fever. Of 122 patients with seroconfirmed measles, 10 patients (all previously vaccinated) had no detectable measles-specific IgM and significantly milder illness than either vaccinated or unvaccinated patients with IgM-positive serum. Of 108 vaccinated patients with seroconfirmed measles, 17 patients (16%) had IgM-negative serology or rash illnesses that failed to meet the clinical case definition; their mean age (13 years), age at the time of vaccination, and time since vaccination did not differ from those of other vaccinated patients. The occurrence of secondary vaccine failure and vaccine-modified measles does not appear to be a major impediment to measles control in the United States but may lead to underreporting of measles cases and result in overestimation of vaccine efficacy in highly vaccinated populations. ( JAMA . 1990;263:2467-2471)

Immunization of Six-Month-Old Infants with Different Doses of Edmonston–Zagreb and Schwarz Measles Vaccines

Abstract: Because measles causes an estimated 2 million deaths per year among children in developing countries, including a substantial proportion of infants less than nine months old — the age at which vaccination is recommended — there has been interest in using different strains of vaccine and higher doses to achieve immunization of younger infants. We conducted a randomized trial of three different doses of Edmonston–Zagreb and of Schwarz measles vaccines in infants to evaluate the effect of the strain and dose of vaccine on the serologic response and acute adverse reactions to vaccination. Six-month-old infants received a standard, medium, or high dose of one of the vaccines, and nine-month-old infants received a standard dose. Antibody levels were measured before and after vaccination, by means of a plaque-reduction neutralization assay, in 1061 six-month-olds and 299 nine-month-olds. Edmonston–Zagreb vaccine produced higher rates of seroconversion and seropositivity than comparable doses of Schwarz ...

Evaluation of WC3 Rotavirus Vaccine and Correlates of Protection in Healthy Infants

Abstract: The safety, immunogenicity, and efficacy of WC3 rotavirus vaccine was evaluated in a double-blind, placebo-controlled trial of healthy infants 2-12 months of age; 103 received one dose of vaccine and 103 received placebo. Vaccination appeared to be safe and induced an antibody response (WC3 neutralizing antibody) in 97% of vaccinees. Only 9 (9%) of these, however, produced antibody to human rotavirus serotypes; at least 7 of the 9 were naturally infected before vaccination. Neither the number of symptomatic episodes of rotavirus diarrhea (21 vs 25) nor the number of moderate to severe rotavirus illnesses (9 vs. 15) was significantly different in vaccine or placebo recipients, respectively, during a predominantly serotype 1 rotavirus season. A slight but significant decrease in mean symptom score was detected in vaccine recipients. Despite an overall lack of efficacy, protection could be correlated to previous rotavirus infection, high levels of WC3 neutralizing antibody, and preexisting (maternal) serotype 1 neutralizing antibody with a titer greater than or equal to 30.

Vaccine prophylaxis of abattoir-associated Q fever: eight years' experience in Australian abattoirs.

Abstract: During the period 1981-8 a clinical trial of a Q fever vaccine (Q-vax; Commonwealth Serum Laboratories, Melbourne) has been conducted in abattoir workers and other at-risk groups in South Australia. Volunteers in four abattoirs and visitors to the abattoirs were given one subcutaneous dose of 30 micrograms of a formalin-inactivated, highly-purified Coxiella burnetii cells, Henzerling strain, Phase 1 antigenic state, in a volume of 0.5 ml. During the period, over 4000 subjects have been vaccinated and the programme continues in the abattoirs and related groups. 'Common' reactions to the vaccine comprised tenderness and erythema, rarely oedema at the inoculation site and sometimes transient headache. Two more serious 'uncommon' reactions, immune abscess at the inoculation site, were observed in two subjects, and two others developed small subcutaneous lumps which gradually dispersed without intervention. Protective efficacy of the vaccine appeared to be absolute and to last for 5 years at least. Eight Q fever cases were observed in vaccinees, but all were in persons vaccinated during the incubation period of a natural attack of Q fever before vaccine-induced immunity had had time (greater than or equal to 13 days after vaccination) to develop. On the other hand, 97 Q fever cases were detected in persons working in, or visiting the same abattoir environments. Assays for antibody and cellular immunity showed an 80-82% seroconversion after vaccination, mostly IgM antibody to Phase 2 antigen, in the 3 months after vaccination. This fell to about 60%, mostly IgG antibody to Phase 1 antigen, after 20 months. On the other hand, 85-95% of vaccinees developed markers of cell mediated immunity as judged by lymphoproliferative responses with C. burnetii antigens; these rates remained elevated for at least 5 years. The Q fever vaccine, unlike other killed rickettsial vaccines, has the property of stimulating long-lasting T lymphocyte memory and this may account for its unusual protective efficacy as a killed vaccine.

Inactivated simian immunodeficiency virus vaccine failed to protect rhesus macaques from intravenous or genital mucosal infection but delayed disease in intravenously exposed animals.

Abstract: Eight rhesus macaques were immunized four times over a period of 8 months with a psoralen-UV-light-inactivated whole simian immunodeficiency virus vaccine adjuvanted with threonyl muramyl dipeptide. Eight unvaccinated control animals received adjuvant alone. Only the vaccinated animals made antibodies before challenge exposure to the viral core and envelope as determined by Western blotting (immunoblotting) and virus-neutralizing antibodies. Ten days after the final immunization, one-half of the vaccinated and nonvaccinated monkeys were challenged exposed intravenously (i.v.) and one-half were challenge exposed via the genital mucosa with virulent simian immunodeficiency virus. All of the nonvaccinated control monkeys became persistently infected. In spite of preexisting neutralizing antibodies and an anamnestic antibody response, all of the immunized monkeys also became persistently infected. However, there was evidence that the clinical course in immunized i.v. infected animals was delayed. All four mock-vaccinated i.v. challenge-exposed animals died with disease from 3 to 9 months postchallenge. In contrast, only one of four vaccinated i.v. challenge-exposed monkeys had died by 11 months postchallenge.

Pathogenicity and immunosuppressive properties of infectious bursal disease "intermediate" strains.

Abstract: This study was conducted to test the pathogenicity and immunosuppressive effects of seven commercially available infectious bursal disease (IBD) vaccines. These vaccine strains are intermediate in their pathogenicity in susceptible specific-pathogen-free (SPF) chickens. One-day-old and 3-week-old SPF chickens were vaccinated with these vaccines. Two weeks after IBD vaccination, they were vaccinated with Newcastle disease virus (NDV). The pathogenic and immunosuppressive effects of the IBD vaccines were evaluated by the antibody response to NDV vaccination, the bursa: body weight index, and histopathological lesions of the bursa. It was found that these strains were highly variable in their virulence and immunosuppressive properties. Three of the strains tested were found to be highly virulent and immunosuppressive; two others were moderate; and two could be classified as mild.

Double-Blind, Placebo-Controlled Trial of a Herpes Simplex Virus Type 2 Glycoprotein Vaccine in Persons at High Risk for Genital Herpes Infection

Abstract: To determine the efficacy of a herpes simplex virus type 2 (HSV-2) glycoprotein subunit vaccine, vaccine (50 micrograms) or placebo was administered intramuscularly at weeks 0, 4, and 22 to 161 persons who lacked HSV-2 antibodies and were sex partners of persons with recurrent genital herpes. The annual rate of acquisition of HSV infection was similar among vaccine and placebo recipients (10.7% and 8%, respectively) but was higher in initially seronegative subjects (15.5%) than in those with HSV-1 at entry (5.9%). Eleven (79%) of the 14 HSV infections acquired during follow-up were symptomatic. Vaccination elicited ELISA antibody titers to glycoproteins gD2 and gB2 that were only 10% and 5%, respectively, of titers found in persons with recurrent genital HSV-2 infection. This vaccine failed to provide protection from acquisition of genital HSV infection. The lack of efficacy appears to be related, in part, to the poor immunogenicity of the vaccine.

Oral vaccination of mice against tetanus by use of a live attenuated Salmonella carrier.

Abstract: A Salmonella typhimurium aroA mutant has been used as a live carrier to immunize mice against tetanus. Plasmid pTETtac4, which expresses a 50-kilodalton fragment of tetanus toxin (fragment C) under the control of the tac promoter, was introduced into SL3261 aroA. When used as a live vaccine and administered orally or intravenously, this strain was able to induce protective immunity in mice against a lethal tetanus toxin challenge. When plasmid pTETtac2, which contains the lacI gene, was used, no immunity was obtained, indicating that the expression of fragment C was repressed in vivo. We believe that this is the first example of a successful oral vaccination that uses an attenuated bacterial carrier to deliver a protective antigen derived from tetanus toxin.

Impact of Measles Vaccination on Childhood Mortality in Rural Bangladesh

Abstract: This study examines the impact of measles vaccination on childhood mortality, based on longitudinal data from the Matlab maternal and child health/family planning programme in rural Bangladesh. It analyses the mortality experience of 8135 vaccinated and 8135 randomly matched nonvaccinated children aged 9-60 months, who were observed from March 1982 to October 1985. The results indicate that measles vaccination had a pronounced impact on both short- and long-term survival--the mortality rates for vaccinated children were as much as 46% less than those for nonvaccinated children. Immunization of children aged up to 3 years with measles vaccine appears to improve significantly their subsequent chances of survival. The findings underscore the need to give greater priority to measles vaccination within primary health care programmes in settings such as rural Bangladesh.

Safety, immunogenicity, and efficacy against cholera challenge in humans of a typhoid-cholera hybrid vaccine derived from Salmonella typhi Ty21a.

Abstract: A live oral vaccine consisting of attenuated Salmonella typhi Ty21a expressing Vibrio cholerae O1 Inaba lipopolysaccharide (LPS) O antigen was constructed and tested in volunteers for safety, immunogenicity, and efficacy. Fourteen adults ingested three doses of 10(10) viable organisms with buffer. One month later, 8 vaccinees and 13 unimmunized controls were challenged with 10(6) pathogenic V. cholerae O1 E1 T or Inaba organisms. No significant adverse reactions to vaccination were observed. All volunteers had significant rises in serum immunoglobulin G (IgG) antibody to S. typhi LPS. Only 2 (14%) of 14 had significant rises in serum IgA or IgG antibody to Inaba LPS, and 5 (36%) of 14 had fourfold rises in vibriocidal antibody. In the challenge study, diarrhea occurred in 13 of 13 controls and 6 of 8 vaccinees (vaccine efficacy, 25%; P = 0.13). The vaccine significantly reduced the severity of the clinical illness (P less than 0.05) and caused decreased excretion of challenge vibrios (P less than 0.05). Although the typhoid-cholera hybrid vaccine did not provide significant protection overall against experimental cholera, this study demonstrates the importance of antibody to V. cholerae O antigen in ameliorating clinical illness and illustrates the use of an S. typhi carrier vaccine strain expressing a foreign antigen.

Incidence of MS during two fifteen-year periods in the Gothenburg region of Sweden.

Abstract: The average annual incidence of definite and probable MS in Gothenburg was re-investigated. For 1950-1954, 1955-1959 and 1960-1964 it was 4.2, 4.2 and 4.3/100,000/year. For the five-year periods between 1974 and 1988 it was 3.0, 2.7 and 2.0/100,000/year. If possible MS was included, the corresponding incidence for 1950-1964 was 5.2, 5.3 and 5.1, and for 1974-1988 it was 3.9, 3.9 and 4.3/100,000/year. Neurological methods and diagnostic criteria were constant throughout the period. The 1950-1964 incidence was based on personally investigated cases, while the 1974-1988 incidence was based partly on review of Gothenburg neurology records. It is concluded that there has been a significant decrease in the incidence of MS in this area. However, the notified decrease may partly be explained by alterations in the case ascertainment procedure. Since the Swedish measles vaccination program started in 1971, the occurrence of measles has been declining and has practically ceased during the 1980s. The time when a possible influence of mass vaccinations against childhood diseases on MS incidence can be monitored is discussed.

Pneumococcal vaccine: efficacy and associated cost savings.

Abstract: We evaluated the efficacy and cost savings of the pneumococcal pneumonia vaccine in a retrospective cohort study of 762 vaccinated and 1161 randomly selected unvaccinated age-sex matched persons in Blue Cross/Blue Shield of Minnesota using medical and pharmaceutical claims. The pneumonia incidence and the ratio of incidence in the postvaccination to prevaccination periods (rate ratio) were examined in the vaccine group by sex and risk factors. Vaccination significantly reduced pneumonia incidence, with overall efficacy of 69% and higher efficacy in women (86%) than in men (33%). We assigned persons to risk categories based on disease conditions as recorded in the claims by the ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) diagnostic codes. In the risk categories, efficacy varied from 50% to 75% and was confounded by sex. Immunocompromised and immunocompetent women had high efficacy (83% to 88%), while immunocompetent and immunocompromised men had lower efficacy (33%). Persons with a precondition of pneumonia exhibited similar vaccine efficacy to the overall cohort relative to the comparison group. Projected costs of pneumonia cases are 3.6 times the observed costs of vaccination and postvaccination pneumonia costs. We conclude that the pneumococcal pneumonia vaccine is efficacious in persons having had pneumonia, persons "at risk" of developing pneumonia, or persons over 50 years of age, and it corresponds to overall savings of $141 per person. ( JAMA . 1990;264:2910-2915)

Use of prior vaccinations for the development of new vaccines

Abstract: There is currently a need for vaccine development to improve the immunogenicity of protective epitopes, which themselves are often poorly immunogenic. Although the immunogenicity of these epitopes can be enhanced by linking them to highly immunogenic carriers, such carriers derived from current vaccines have not proven to be generally effective. One reason may be related to epitope-specific suppression, in which prior vaccination with a protein can inhibit the antibody response to new epitopes linked to the protein. To circumvent such inhibition, a peptide from tetanus toxoid was identified that, when linked to a B cell epitope and injected into tetanus toxoid-primed recipients, retained sequences for carrier but not suppressor function. The antibody response to the B cell epitope was enhanced. This may be a general method for taking advantage of previous vaccinations in the development of new vaccines.