Smallpox revaccination of 21000 first responders in Israel: lessons learned.

OBJECTIVES: Between July 2002 and April 2003, over 21000 individuals were revaccinated against smallpox by the Israeli Ministry of Health. The objectives of the campaign were to create an immunized core of first responders, to review vaccination techniques, and to produce vaccinia immune globulin (VIG). METHODS: The Lister strain of vaccinia virus was used at a concentration of approximately 10(7) pock-forming units (PFU)/ml, and was administered by the multiple-puncture technique. The revaccinees were from varied ethnic backgrounds, almost all were aged 25-64 years, and all participants had been vaccinated against smallpox in the past. RESULTS: The proportion of clinical take was 66.1% (95% CI: 65.2%, 67.0%), similar to past vaccination programs when take also occurred in approximately two thirds of vaccinees. An antibody response occurred in 77.7% (95% CI: 74.8%, 80.6%) of all revaccinees: 94.4% (95% CI: 91.8%, 96.3%) of those with clinical take and 56.6% (95% CI: 51.3%, 61.8%) of those without clinical take. The most common side effects corresponded to symptoms of non-specific viral diseases, and only a few revaccinees reported serious side effects. CONCLUSIONS: The campaign achieved all its basic goals and provided useful lessons for any mass-vaccination programs that might be necessary in the future.

European seroepidemiology network 2: Standardisation of assays for seroepidemiology of varicella zoster virus.

BACKGROUND: The aim of the European Sero-Epidemiology Network (ESEN2) is to harmonise the serological surveillance of vaccine-preventable diseases in Europe. OBJECTIVE: To allow comparison of antibody prevalence in different countries by standardising results into common units. STUDY DESIGN: For varicella zoster virus (VZV), a reference laboratory established a panel of 148 samples, characterised by indirect enzyme-immunoassay (ELISA), indirect immunofluorescence, and complement fixation test. Fifty-seven samples were also studied by the fluorescence antibody to membrane antigen test. The geometric mean of the antibody activity (GMAA) obtained from four ELISA determinations was used to characterise each sample of the panel as positive (GMAA: >100 mIU/ml), equivocal (GMAA: 50-100 mIU/ml) or negative (GMAA: <50 mIU/ml) for antibody to VZV (anti-VZV). Thirteen laboratories, using five different ELISA tests, tested the panel. RESULTS: Agreement with the reference laboratory was above 85% in all cases, and the R(2) values obtained from regression analysis of the quantitative results were always higher than 0.87. Finally, the regression equations could be used to convert national values into a common unitage. CONCLUSION: This study confirmed that results for anti-VZV obtained by different ELISA methods can be converted into common units, enabling the comparison of the seroprevalence profiles obtained in the participant countries.

Laboratory assessment and diagnosis of congenital viral infections: Rubella, cytomegalovirus (CMV), varicella-zoster virus (VZV), herpes simplex virus (HSV), parvovirus B19 and human immunodeficiency virus (HIV).

Viral infections during pregnancy may cause fetal or neonatal damage. Clinical intervention, which is required for certain viral infections, relies on laboratory tests performed during pregnancy and at the neonatal stage. This review describes traditional and advanced laboratory approaches and testing methods used for assessment of the six most significant viral infections during pregnancy: rubella virus (RV), cytomegalovirus (CMV), varicella-zoster virus (VZV), herpes simplex virus (HSV), parvovirus B19 and human immunodeficiency virus (HIV). Interpretation of the laboratory tests results according to studies published in recent years is discussed.

Determination of immunity to vaccinia virus by using diluted inactivated vaccinia vaccine solution for skin testing.

AIMS: We evaluated the usefulness of skin test prepared by inactivation of vaccinia vaccine in predicting immunity to vaccinia. Skin test was injected to 77 healthy adults. Twenty had a recent smallpox vaccination (group 1). Thirty-seven were long term vacinees (group 2), while 20 subjects had never been vaccinated for smallpox (group 3). RESULTS: Mean size of induration was 7.9, 5.3 and 0.4 mm for subjects from groups 1, 2 and 3, respectively (P<0.03 for difference between groups). Induration >or=5 mm correlated with neutralizing antibody titer >1:32 (r=0.73, P<0.0001). CONCLUSIONS: The skin test is a potentially useful tool for the assessment of immunity to vaccinia.

Presence of viremia in patients with primary herpetic gingivostomatitis.

BACKGROUND: Presence of viremia during primary herpes simplex virus (HSV) infections has been previously investigated, but the findings for immunocompetent individuals have only rarely been reported. METHODS: With use of polymerase chain reaction (PCR), we evaluated blood samples obtained from children with primary herpes simplex virus (HSV) gingivostomatitis for viremia. RESULTS: There were 16 girls and 16 boys, aged 9-44 months (median age, 19 months). Serological test results for HSV type 1 were positive for 3 subjects (10.3%), borderline for 7 (24.1%), and negative for 19 (65.5%). Results of PCR of peripheral blood samples were positive for 11 subjects (34.4%). Time from disease onset to specimen collection was 24-216 h (median, 72 h) and was longer for subjects with positive results of serological tests (P =.014) and shorter for subjects with positive PCR results (P=.42). No cases with positive results of both PCR and serological tests were found. CONCLUSION: PCR detected viremia in 34% of patients with primary herpetic gingivostomatitis. Presence of viremia may play a potential role in viral dissemination, providing a better understanding of the pathogenesis of HSV infections, especially of the central nervous system.

A sero-epidemiological study of herpes virus type 1 and 2 infection in Israel.

In order to obtain data on the prevalence and incidence of herpes virus type 2 (HSV(2)) infection in selected populations of women and to identify groups that might benefit from routine prenatal screening, an epidemiological study was conducted during the period 1984-1990, which showed HSV(2) seroprevalence to be 2.8%. Due to the worldwide increase of over 30% of HSV(2) infection in the past two decades, a second study was performed during the period 1 January 1998-31 December 1999. Four different population groups were studied: 172 children aged 6 months to 17 years (group 1), 716 adults, men and women aged 18-95 (group 2), 200 women aged 30-67 who participated in the first survey and were re-examined in 1999 in the second survey (group 3), and a prevalence group of 155 parturient women from six different delivery rooms (group 4). Among the healthy 716 males and females HSV(2) seroprevalence was 4.5%. When analyzed by subgroup, HSV(2) seroprevalence rose from 2.3% in the 18-30 years subgroup to 6.5% in the 30-50 years subgroup and to 7.3% in the 51-70 years subgroup, and then declined to 2.4% after age 70 years. In the 200 women re-examined, HSV(2) seroprevalence was 7.7% with a 0.55% HSV(2) sero incidence per annum. In the prevalence group HSV(2) seroprevalence was 4.5%. Sera from the 1223 participants of all four groups were also screened for HSV(1) infection. HSV(1) antibody was present in 22% of children aged 6 months-1 year, in 60% at 21 years and in 87% at age 70 years. The data support the conclusion that in Israel there is no justification for routine prenatal HSV(2) screening in the healthy female population.