Standardization of measles, mumps and rubella assays to enable comparisons of seroprevalence data across 21 European countries and Australia

The aim of the European Sero-Epidemiology Network is to establish comparability of the serological surveillance of vaccine-preventable diseases in Europe. The designated reference laboratory (RL) for measles, mumps, rubella (MMR) prepared and tested a panel of 151 sera by the reference enzyme immunoassay (rEIA). Laboratories in 21 countries tested the panel for antibodies against MMR using their usual assay (a total of 16 different EIAs) and the results were plotted against the reference results in order to obtain equations for the standardization of national serum surveys. The RL also tested the panel by the plaque neutralization test (PNT). Large differences in qualitative results were found compared to the RL. Well-fitting standardization equations with R20·8 were obtained for almost all laboratories through regression of the quantitative results against those of the RL. When compared to PNT, the rEIA had a sensitivity of 95·3%, 92·8% and 100% and a specificity of 100%, 87·1% and 92·8% for measles, mumps and rubella, respectively. The need for standardization was highlighted by substantial inter-country differences. Standardization was successful and the selected standardization equations allowed the conversion of local serological results into common units and enabled direct comparison of seroprevalence data of the participating countrie

Treatment-associated polymorphisms in protease are significantly associated with higher viral load and lower CD4 count in newly diagnosed drug-naive HIV-1 infected patients

Peer reviewe

Transmission of Drug‐Resistant HIV‐1 is Stabilizing in Europe

The SPREAD Programme investigated prospectively the time trend from September 2002 through December 2005 of transmitted drug resistance (TDR) among 2793 patients in 20 European countries and in Israel with newly diagnosed human immunodeficiency virus type 1 (HIV‐1) infection. The overall prevalence of TDR was 8.4% (225 of 2687 patients; 95% confidence interval [CI], 7.4%–9.5%), the prevalence of nucleoside reverse‐transcriptase inhibitor (NRTI) resistance was 4.7% (125 of 2687 patients; 95% CI, 3.9%–5.5%), the prevalence of nonucleoside reverse‐transcriptase inhibitor (NNRTI) resistance was 2.3% (62 of 2687 patients; 95% CI, 1.8%–2.9%), and the prevalence of protease inhibitor (PI) resistance was 2.9% (79 of 2687 patients; 95% CI, 2.4%–3.6%). There was no time trend in the overall TDR or in NRTI resistance, but there was a statistically significant decrease in PI resistance ( ) and in NNRTI resistance after an initial increase ( ). We found that TDR appears to be stabilizing in Europe, consistent with recent reports of decreasing drug resistance and improved viral suppression in patients treated for HIV‐1 infection

Standardization of measles, mumps and rubella assays to enable comparisons of seroprevalence data across 21 European countries and Australia

The aim of the European Sero-Epidemiology Network is to establish comparability of the serological surveillance of vaccine-preventable diseases in Europe. The designated reference laboratory (RL) for measles, mumps, rubella (MMR) prepared and tested a panel of 151 sera by the reference enzyme immunoassay (rEIA). Laboratories in 21 countries tested the panel for antibodies against MMR using their usual assay (a total of 16 different EIAs) and the results were plotted against the reference results in order to obtain equations for the standardization of national serum surveys. The RL also tested the panel by the plaque neutralization test (PNT). Large differences in qualitative results were found compared to the RL. Well-fitting standardization equations with R2≥0.8 were obtained for almost all laboratories through regression of the quantitative results against those of the RL. When compared to PNT, the rEIA had a sensitivity of 95.3%, 92.8% and 100% and a specificity of 100%, 87.1% and 92.8% for measles, mumps and rubella, respectively. The need for standardization was highlighted by substantial inter-country differences. Standardization was successful and the selected standardization equations allowed the conversion of local serological results into common units and enabled direct comparison of seroprevalence data of the participating countries. © 2007 Cambridge University Press

European Seroepidemiology Network 2: standardisation of assys 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