Pertussis seroprevalence among adults of reproductive age (20-39 years) in fourteen European countries.

The reported incidence of pertussis in European countries varies considerably. We aimed to study specific Bordetella pertussis seroprevalence in Europe by measuring serum IgG antibody levels to pertussis toxin (anti-PT IgG). Fourteen national laboratories participated in this study including Belgium, Denmark, Finland, Greece, Hungary, Italy, Lithuania, Malta, Norway, Poland, Portugal, Romania, Spain, and Sweden. Each country collected approximately 250 samples (N = 7903) from the age groups 20-29 years (N = 3976) and 30-39 years (N = 3927) during 2010-2013. Samples were anonymous residual sera from diagnostic laboratories and were analyzed at the national laboratories by a Swedish reference method, a commercial ELISA kit, or were sent to Sweden for analysis. The median anti-PT IgG concentrations ranged from 4 to 13.6 IU/mL. The proportion of samples with anti-PT IgG ≥100 IU/mL, indicating a recent infection ranged from 0.2% (Hungary) to 5.7% (Portugal). The highest proportion of sera with anti-PT IgG levels between 50 and <100 IU/mL, indicating an infection within the last few years, was found in Portugal (12.3%) and Italy (13.9%). This study shows that the circulation of B. pertussis is quite extensive in adults, aged 20-39 years, despite well-established vaccination programs in Europe.

Respiratory syncytial virus activity and climate parameters during a 12-year period.

The epidemic pattern of respiratory syncytial virus (RSV) infection during long periods and the factors that determine seasonality are not well studied. In order to correlate the RSV epidemic activity with climate parameters, we conducted a retrospective study of children (0-14 year) who were hospitalized because of respiratory tract infection and had an RSV test performed in the major tertiary pediatric hospital of Greece during a 12-year period (2002-2013). Daily data regarding temperature and humidity were obtained from the Hellenic National Meteorological Service. A total of 2030/7516 (27%) children were tested positive for RSV infection. Among RSV positive children 1945/2030 (95.8%) were infants <1 year. A peak of RSV activity was measured in years 2002, 2003, and 2006 (>35% positive). The RSV season in our area spanned from December to April, with higher incidence during January through March. The peak monthly RSV incidence was observed during February with mean temperature 10.34 °C and mean relative humidity 69.16%. Regarding climate conditions, a statistically significant positive correlation was found between monthly RSV activity and mean monthly relative humidity (rho = 0.66, P-value = 0.02), whereas a negative correlation was found with mean monthly temperature (rho = -0.81, P-value = 0.002). However, in the multivariable analysis, only the effect of mean monthly temperature remained statistically significant (IRR = 0.72, 95% CI: 0.68, 0.80). Further understanding of RSV seasonality in different geographic areas would be important in order to timely implement preventing strategies with immunoprophylaxis or future RSV vaccines.