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Although nine of 16 federal states in Germany conduct public health surveillance for Lyme borreliosis (LB), the extent of under-ascertainment is unknown. As a model for European countries that conduct LB surveillance, we sought to estimate the population-based incidence of symptomatic LB after adjusting for under-ascertainment. Estimating seroprevalence-derived under-ascertainment relies on data from seroprevalence studies, public health surveillance, and published literature. The number of symptomatic LB cases in states that conduct LB surveillance was estimated from studies reporting the seroprevalence of antibodies against Borrelia burgdorferi sensu lato, the proportion of LB cases that are asymptomatic, and the duration of antibody detection. The number of estimated incident symptomatic LB cases was compared with the number of surveillance-reported LB cases to derive under-ascertainment multipliers. The multipliers were applied to the number of 2021 surveillance-reported LB cases to estimate the population-based incidence of symptomatic LB in Germany. Adjusting for seroprevalence-based under-ascertainment multipliers, the estimated number of symptomatic LB cases in states that conducted surveillance was 129,870 (408 per 100,000 population) in 2021. As there were 11,051 surveillance-reported cases in 2021 in these states, these data indicate there were 12 symptomatic LB cases for every surveillance-reported LB case. We demonstrate that symptomatic LB is underdetected in Germany and that this seroprevalence-based approach can be applied elsewhere in Europe where requisite data are available. Nationwide expansion of LB surveillance would further elucidate the true LB disease burden in Germany and could support targeted disease prevention efforts to address the high LB disease burden. [ABSTRACT FROM AUTHOR]

Abstract: Background: During the pandemic of the 2009 A(H1N1) influenza virus strain, 20–40% of the population in some areas were infected. Infection with A(H1N1) may be mild, with an average case fatality rate below 0.25%, but severe disease is not limited to patients with underlying medical conditions. Since A(H1N1) is expected to continue to circulate it is included in the seasonal influenza vaccines for the 2010–2011 winter season. We investigated the immunogenicity and safety of a preservative-free non-adjuvanted seasonal trivalent influenza vaccine. Methods: We conducted a single center single-arm study involving 142 subjects (77 adults of 18–60 years and 65 subjects 61 years and above) to test the immunogenicity, safety, and tolerability of a trivalent split influenza vaccine. The vaccine contained 15μg of hemagglutinin of each of the virus strains recommended for the 2010–2011 northern hemisphere winter season (A/California/7/2009 (H1N1)-like strain; A/Perth/16/2009 (H3N2)-like strain; B/Brisbane/60/2008-like strain) in a non-adjuvanted preservative-free formulation. Antibody response to each antigen was measured by hemagglutination inhibition (HI) 21 days after immunization. Subject diary cards and additional telephone interviews were used to assess the safety profile. Results: By day 21 after the vaccination, seroconversion, or a 4-fold antibody increase in HI antibody titers, was detectable against A(H1N1) in 84% and 75% of younger and older adults, against A(H3N2) in 80% and 57%, and against the B influenza strain in 61% and 33%. HI antibody titers of 40 or more were observed against A(H1N1) in 99% and 90% of younger and older adults, against A(H3N2) in 100% and 90%, and against the B influenza strain in 91% and 78%. Pre-vaccination antibody titers were protective against A(H1N1), A(H3N2), and B in 26%, 44% and 33%, respectively of the adults below 61 years and in 27%, 54% and 44% of the subjects of 61 years and above. Local and systemic reactions were more common in younger than in older subjects and the most frequently reported reactions were pain at the injection site (36%), myalgia (24%), and fatigue (15%). Five percent elderly subjects and 1% of younger subjects had mild or moderate unsolicited adverse events such as prolonged ecchymosis or night sweats that resolved within 7 days after vaccination. Conclusions: This single dose trivalent seasonal influenza vaccine generated protective antibodies to all three viral strains and had an acceptable safety profile in both younger and older adults (ClinicalTrials.gov identifier: NCT01147081). [Copyright &y& Elsevier]