Immunity status against poliomyelitis in Germany: determination of cut-off values in International Units.
BACKGROUND
To prevent importations of wild polioviruses into a polio free region a high level of population immunity must be kept. Standard methodology for determination of polio antibodies is a feature aimed at obtaining consistent results. An International Standard Serum for polio antibodies exists, but no protective level in International Units is defined.


METHODS
A representative study was carried out in order to determine the serological status against poliomyelitis in Germany (n = 2564, age 18-79 years). Furthermore, sera from persons aged less than 18 years were included (n = 881). Microneutralization test has been used for determination of antibody levels. Results have been expressed in International Units.


RESULTS
The results of this study indicate that the cut-off level for polio antibodies is 0.075 IU/ml for Polio 1, 0.180 IU/ml for Polio 2 and 0.080 IU/ml for Polio 3. Neutralizing antibodies against poliovirus type 1, 2 and 3 were detected in 96.2%, 96.8% and 89.6% of samples, respectively.


CONCLUSIONS
Overall, this seroprevalence indicates a very high level of immunity of the general population. It must be kept after the switch of immunization strategy from attenuated to inactivated vaccine in Germany.
Diedrich
Sabine
S
Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany. DiedrichS@rki.de
Claus
Hermann
H
Schreier
Eckart
E
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D004198:Disease Susceptibility / Q000276:immunology; D005260:Female; D005858:Germany; D006801:Humans; D007113:Immunity, Innate; D007115:Immunization Schedule; D007394:International System of Units / Q000592:standards; D008297:Male; D008432:Mathematical Computing; D008875:Middle Aged; D009500:Neutralization Tests / Q000592:standards*; D011051:Poliomyelitis / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control* / Q000635:transmission; D017955:Poliovirus / Q000276:immunology*; D023321:Poliovirus Vaccines / Q000627:therapeutic use; D011159:Population Surveillance / Q000379:methods; D012015:Reference Standards; D012737:Sex Factors
D000914:Antibodies, Viral; D023321:Poliovirus Vaccines