Directigen Flu A, an enzyme immunoassay membrane test for the detection of influenza A virus, was compared with serum hemagglutinine inhibition assay in adult and elderly patients.Throat specimens were collected by vigorous swabbing from febrile patients who were suspect for influenza by clinical symptoms and tested with Directigen Flu A. Serum samples were collected from the patients at onset of illness and two to eleven weeks later and tested for antibody titer to influenza A/H1N1, A/H3N2, and B. A total of 57 patients were involved in this study; 32 under 59 years of age and 25 over 60 years of age.Influenza was diagnosed in 42 patients by HI titer elevation (73.7%). Directigen Flu A was positive in 25 patients. Results of Directigen Flu A and HI test agreed in 40 patients. Sensitivity and specificity of Directigen Flu A were 59.5% (25/42) and 100% (15/15), respectively. There was no significant difference in sensitivity between the two age groups.These results indicate the potential usefulness of Directigen Flu A in the surveillance of influenza A infection in the geriatric population. Directigen Flu A gives results within 15 minutes without expensive equipment. Use of Directigen Flu permits the timely administration of antiviral therapy and infection control among hospitalized and institutionalized geriatric patients.
To determing the efficacy of a single influenza vaccine administration in the elderly receiving annual influenza vaccination, antibody response to influenza vaccine was compared between once and twice injections in a geriatric cohort. Influenza vaccination had been done for 69 inpatients in the year prior to the study, and was administered twice for 34 of them and once for the other 35 during the study period. Influenza vaccine was injected twice to 77 inpatients who had not received influenza vaccine in the year prior to the study.Hemoagglutination inhibition (HI) antibody titer for influenza A/H1N1, A/H3N2, and B was measured before vaccination, after the first vaccination, after the second vaccination, and after the epidemic period, September 1995 to April 1996. HI antibody titer prior to vaccination was significantly higher in the patients who had received influenza vaccination the previous year. The influenza vaccine induced an increase in HI titer in almost all subjects, and the geometric mean of the HI titer after vaccination in the patients who received vaccine once was comparable to that of the patients injected vaccine twice. The number of patients with HI titers of over 128×increased, and the frequency ranged from 60.0% to 97.1% for the influenza viruses of the three subtypes. The frequency of HI titers over 128×was not significantly different among the three groups. The second vaccination did not increase the number of patients with HI titers over 128×when compared with the number after the first injection in the patients who had received influenza vaccine the previous year. These results suggest that prior vaccination does not diminish the antibody response to influenza vaccine in the elderly. The efficacy of a single influenza vaccination is comparable to that achieved by twice injections in the elderly receiving annual influenza vaccination.
An outbreak of an influenza like illness was found in a nursing home in Fukuoka in January, 1999. Results of hemagglutinine inhibition tests with paired sera of patients and rapid diagnosis kit for influenza A indicated that an influenza A (H3N2) outbreak had occurred. A total of 15 patients with influenza like illness from one residential area of the nursing home were administered amantadine, 100mg per day for five days. Clinical records of 264 residents were surveyed retrospectively from the tenth to the thirty-first of January, 1999. Influenza like illness was found in 112 residents (42.4%). The incidence of influenza like illness differed by residential area, ranging from 27.6% to 54.0%. The mean duration of fever was 3.6 days among patients administered amantadine. The mean duration was 4.4days for patients not administered amantadine. The incidence of influenza like illness decreased rapidly after amantadine administration in the residential area where amantadine administration was done. These results suggest that amantadine is effective in mitigating influenza symptoms in the elderly. Amantadine may be useful for diminishing the influence of influenza A outbreaks in nursing homes.
To investigate the effect of previous influenza vaccination and the difference in antibody induction by single and twice injection of influenza vaccine in the elderly, hemagglutination inhibition (HI) antibody titers of the three types of influenza viruses were measured .Influenza vaccination was done for 217 inpatients. For the patients who had influenza vaccination in the year prior to the study, influenza vaccine was administered once to 77 patients and twice to another 70 patients. Influenza vaccine was injected twice to 70 patients who had not received influenza vaccine in the previous years.The influenza vaccine induced an increase in HI titer in almost all patients . The geometric mean of the HI titer and the frequency of patients with HI titers over 128x were similar after vaccination in the groups of patients who were injected twice, irrespective of whether or not influenza vaccination was given in the year prior to the study. The geometric means of the HI titers for influenzas A/H3N2 and B and the frequency of HI titers over 128x for influenza A/H3N2 after vaccination were lower in the patients who received vaccine once than in the patients vaccinated twice.These results suggest that prior vaccination does not diminish antibody response to influenza vaccine significantly in the elderly when influenza vaccine is injected twice . Although single injection is inferior to twice injection in antibody induction with some vaccine virus strains, induction of HI titers over 128x is found in more than 70% of elderly. Single injection of influenza vaccine may be practically effective and useful for protection of influenza infection in the elderly .
Monoclonal antibody has the characteristics of high purity, specificity and strong activity. For this reason, we adopted a monoclonal antibody (R-McAb), against rubella to coat the polystyrene EIA microtitration plate for the first step. Then we followed an indirect enzyme immunoassay to detect rubella immunoglobulin G antibody. We call this method the indirect mix enzyme immunosorbent assay (IMEIA). The 257 serum specimens collected from different human groups tested by this assay (IMEIA) and rubella hemagglutination inhibitiion (HAI) test gave a 100% agreement.
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