[Serologic assessment of measles herd immunity in the north-western region of Romania]. / Studiu serologic de evaluare a imunitatii populationale fata de rujeola în, zona de nord-vest a României.

The most objective analysis of measles herd immunity could be made by sero-epidemiological study. In the population of North-West area of Romania we have evaluated the measles immune protection through a seroprevalence study, using an age stratified sample of population in witch the subjects from Cluj and Bistrita-Nasaud counties were voluntarily involved. The measles antibody concentration was determined by immunoassay method using Hycor test. The database was performed in Microsoft Access and the statistics in Epi Info 2000. Levels higher then 40 arbitrary units (the cut-off of protection) of the measles antibody were met in 80% (IC95% : 75.09-84.01) of all subjects, 82.4% of the females and 84.9% of the urban area peoples. 98.3% of all subjects had detectable antibody levels. The protection increased by age: the adults had protective levels in at least 90% of cases. Global vaccine efficacy was 64.7% (IC95 % : 56.5 - 72.9), moderately decreasing with increasing age (the correlation coefficient--58.1%). In the assessed sample, the measles protection was the highest in adults, women and subjects from urban areas. The vaccine efficacy was relatively small, but the majority of subjects had detectable titers of measles antibody.

[How protective is the immunization against viral hepatitis B prospectively? Seroprevalence study on viral hepatitis B infection]. / Cât de protectoare în timp este vaccinarea împotriva hepatitei virale B? Studiu de seroprevalenta privind infectia cu virusul hepatitic B.

Sero-epidemiological studies on herd immunity following the vaccination against hepatitis B virus may contribute to assess the needs and the optimal calendar of some booster vaccinations against hepatitis B. Such studies are quite uncommon. In order to evaluate the immune protection at community scale we performed a seroprevalence study using a sample of 360 volunteer subjects stratified in 9 groups of age. Sterile sera were obtained and preserved as frozen at -20 degrees C, and antibodies against HBsAg were measured using ELISA kits made by Dia Sorin, Italy. Data base and statistical processing of data have been made using Access, Epi Info and Excel software. 60.3% of subjects proved having protective seric levels of Anti-HBs, significantly prevailing in female subjects (68.8% ; p < 0,001) and in urban population (62.8%; p <0,001). The general trend of Anti-HBs by age varied insignificantly (correlation coefficient 0.6%); the values were significantly lower in the groups of 10-14 years of age (39.4%; p<0,001) and in 15-19 years of age (40%; p<0,001). The serum levels of Anti-HBs varied between maximum a of 1.970 mUI/ml and a minimum of 1 mUI/ml, the geometric average being of 41 mUI/ml (standard deviation 27.3 ; IC 95% : (38.18-43.82)). The vaccine efficacy for the level considered as protective (10 mUI/ml) has been 81.9% (IC 95% : (76.1-87.7)). The protection against hepatitis B viral infection assessed by measuring the prevalence of Anti-HBs is significantly more frequent in female subjects and in urban population. The trend of serum level of Anti-HBs by age, having irrelevant variations by age, has been induced by vaccination against hepatitis B virus starting 1995. The efficacy of vaccinations in newborns and health care personnel, in the field populations, was as high as 81.9%.