Evaluation of a personalized, dose-sparing revaccination strategy in hepatitis B vaccine non-responders.

OBJECTIVES: The detection of low levels of antibodies against HBsAg (anti-HBs) below 10 IU/L in non-responders after a primary hepatitis B vaccination, is associated with seroconversion after revaccination. We compared the diagnostic performance of four anti-HBs assays in non-responders in their ability to differentiate between absence or presence of low levels of anti-HBs and propose a revaccination strategy guided by anti-HBs titres. METHODS: Non-responders were revaccinated with Fendrix 20 µg at 0, 1 and 2 months. Anti-HBs titres were determined by Abbott Architect, Diasorin Liaison, Roche Cobas and Siemens ADVIA Centaur. Inter-assay agreement was evaluated with Cohen's Kappa (k) in baseline samples between zero-responders without detectable antibodies and poor-responders with detectable antibodies < 10 IU/L. Seroconversion rates and geometric mean titres were analysed at 0, 1 and 3 months. A titre-based strategy (one revaccination dose and anti-HBs measurement followed by two more revaccination doses if required) was compared with the standard revaccination series of 3 doses. RESULTS: 57 participants were included in the analysis. k was ≥ 0.65 for all assays except ADVIA (k ≤ 0.41). After one revaccination dose all assays detected a mean seroconversion rate in zero-responders of 42.9%, compared to 85.1% in poor-responders. The difference between zero- and poor-responders in seroconversion rate per assay was significant (p < 0.05). After three revaccination doses the mean seroconversion rate was 88.2% in zero-responders and 98.5% in poor-responders (p > 0.286 per assay). A titre-based strategy reduced the amount of revaccinations by 17% compared with the standard. CONCLUSIONS: All assays demonstrated a comparable difference in seroconversion rate between zero- and poor-responders after one revaccination dose. The revaccination strategy could be optimised by differentiation between zero- and poor-responders followed by a titre-guided schedule.

[At the heart of the Dutch COVID-19 epidemic: experiences of a municipal health service and a look at the future]. / In het hart van de Nederlandse covid-19-epidemie.

COVID-19 first appeared in the Netherlands at the end of February 2020. North Brabant province was the epicentre, which led the municipal health service (GGD) 'Hart voor Brabant' to register 1495 cases in a single month in its area. As the GGD spearheaded the fight, it was faced with a rapid increase to a major epidemic. We describe the experiences of the GGD 'Hart voor Brabant' on the basis of a GGD's responsibilities. An epidemic consists of several stages, each with its own focus with respect to source and contact tracing and diagnostic testing. An epidemic of this magnitude is usually associated with common healthcare challenges, for example limited availability of diagnostic resources and personal protective equipment. Now that the government is easing the measures, early source identification and rapid start-up of contact tracing are particularly important. The big challenge now is to convince COVID-19 patients' contacts to stick to all control measures.

Two Community Clusters of Legionnaires' Disease Directly Linked to a Biologic Wastewater Treatment Plant, the Netherlands.

A biologic wastewater treatment plant was identified as a common source for 2 consecutive Legionnaires' disease clusters in the Netherlands in 2016 and 2017. Sequence typing and transmission modeling indicated direct and long-distance transmission of Legionella, indicating this source type should also be investigated in sporadic Legionnaires' disease cases.