Evaluation of the infectivity, immunogenicity, and efficacy of live cold-adapted influenza B/Ann Arbor/1/86 reassortant virus vaccine in adult volunteers

Article Abstract:

Despite the fact that the influenza B virus changes at only about one-fifth the rate of the influenza A virus, influenza B still manages to produce flu epidemics among children and young adults every three to four years. Influenza B can produce croup and high fever in infants, and may cause Reye's syndrome in children. In the elderly, lower respiratory tract disease resulting from influenza B can be fatal. Currently, licensed influenza B vaccines are made from inactivated virus, and are generally less effective than vaccines against influenza A. Since vaccines composed of live viruses are generally more effective, as well as being more dangerous, an attempt was made to produce a safe, effective influenza B vaccine from a cold-adapted reassortant virus. Influenza viruses are unusual among viruses in that their genetic RNA is arranged in eight distinct and separate segments of RNA which act very much like viral "chromosomes". As a result, when two different viral isolates are grown in the same cell culture, the progeny virus will all contain eight RNA segments, but some of the eight will be from one parent, and some from the other, in all possible combinations. This provides a splendid opportunity for the vaccine maker. In the case of influenza B, researchers prepared a virus variant which grew well at 25 degrees centigrade, but not so well at 37 degrees, or body temperature. While this cold-adapted virus itself would make a poor vaccine, it can be rapidly combined with examples of whatever virus is currently posing the greatest threat of epidemic. After growing the two viruses together, researchers isolate reassortants with two of the RNA segments containing the genes for the most immunogenic virus proteins of the wild virus, and the other six RNA segments come from the cold-adapted, poorly growing laboratory parent. A test of the new cold-adapted vaccine in volunteers showed that it completely protected its recipients. However, the safety and efficacy of the vaccine has not yet been established for patients other than healthy adults. (Consumer Summary produced by Reliance Medical Information, Inc.)

---

Cold recombinant influenza B/Texas/1/84 vaccine virus (CRB 87): attenuation, immunogenicity, and efficacy against homotypic challenge

Article Abstract:

Alternative vaccines and immunogens are being sought to augment or replace immunizing agents currently in use. Live, weakened, recombinant (manufactured), cold-adapted (CR) influenza vaccines are currently undergoing evaluation as alternatives to killed influenza vaccines. Recombinant forms of type A influenza virus have been shown to be well tolerated, immunogenic, genetically stable, and non-transmissible. Short term immunity (1 to 2 years), elicited by intranasal instillation, has been achieved with CR influenza A vaccines. Protection thus obtained appears to be equal to that provided by parental administration (usually injection) in young adults. This study describes efforts to produce similar vaccines using type B influenza viruses, CR influenza B/Texas/1/87 (CRB87). The reactogenicity, immunogenicity in young adults, and protective efficacy against homologous challenge with CRB87 are presented. Volunteers between 18 and 35 year of age constituted the study group. They were screened for susceptibility to the test viruses, and only those with low levels or undetectable antibody levels were included. Individuals with allergy to eggs, those who were pregnant, and those with acute or chronic illness were excluded. Participants were randomly assigned to receive increasing doses of the CRB87 virus or an appropriate placebo. Symptomatic and clinical responses were documented. Only the highest dose of CRB87 produced a high frequency of serum antibody responses (the ability to fight the invading antigen). Most participants receiving lower doses became infected. Those who were rechallenged with CRB87 three to four months later showed a significantly lower level of infection, less virus shedding, and milder upper respiratory symptoms, than those challenged with a similar dose for the first time. The results suggest that CRB87 is an immunogenic, attenuated vaccine that can protect against challenge with the same virus in a manner similar to type A counterparts. (Consumer Summary produced by Reliance Medical Information, Inc.)

---

Safety and immunogenicity of live attenuated cold-adapted influenza B/Ann Arbor/1/86 reassortant virus vaccine in infants and children

Article Abstract:

Influenza B virus (IBV) is an important cause of febrile (fever-causing) respiratory disease in children. IBV infections account for a significant percentage of school absenteeism during outbreaks. They have been strongly associated with Reye's syndrome, a frequently occurring fatal disease associated with influenza and varicella (chickenpox) infections. Inactivated IBV vaccines provide variable response levels in recipients. A cold-adapted live influenza vaccine was prepared by assembling specific hemagglutinin (HA) and neuraminidase (NA) genes from the influenza strain known as B/Ann Arbor/1/86, and RNA segments from a donor virus, influenza B/Ann Arbor/1/66. This new virus vaccine was administered to 13 seropositive children (who had IBV antibodies, an indication of prior infection). Five seropositive children received placebo. The morbidity (rate of illness) in the vaccinees was lower than in the placebo group, and the vaccine was demonstrated to be safe in seropositive children. Subsequently, 57 seronegative children (without antibodies against IBV) were studied; 37 received vaccine, and 20 were given placebo. Increased levels of antibodies against IBV were identified in the seronegative vaccine recipients. The new vaccine was found to be immunogenic, safe and phenotypically stable, occasionally producing mild upper respiratory disease, in seronegative infants and children. (Consumer Summary produced by Reliance Medical Information, Inc.)

Physiological aspects

Similar abstracts:

• Abstracts: A comparative trial of the reactogenicity and immunogenicity of Takeda acellular pertussis vaccine combined with tetanus and diphtheria toxoids
• Abstracts: A Phase I evaluation of the safety and immunogenicity of vaccination with recombinant gp160 in patients with early human immunodeficiency virus infection
• Abstracts: Measles incidence, vaccine efficacy, and mortality in two urban African areas with high vaccination coverage. Patterns of transmission and severity of measles infection: a reanalysis of data from the Machakos area, Kenya
• Abstracts: Measles incidence, vaccine efficacy, and mortality in two urban African areas with high vaccination coverage. part 2
• Abstracts: Gene transfer into humans - immunotherapy of patients with advanced melanoma, using tumor-infiltrating lymphocytes modified by retroviral gene transduction

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.