Eurosurveillance - Volume 28, Issue 25, 22 June 2023

Pneumococcal conjugated vaccine (PCV)7 and PCV13 programmes started in Israel from July 2009 and November 2010 respectively, with a 2+1 schedule (one dose at 2 months old, one at 4 months old, and a booster dose at 12 months old). Thereafter, invasive pneumococcal disease (IPD) rates substantially declined in children. Uptake of all three doses in < 2-year-olds since 2012 is > 90%. For still incompletely vaccinated infants (≤ 12 months old), how well the PCV 2+1 programme shields from IPD is not fully resolved.

To assess the adequacy of protection conferred by the 2+1 schedule PCV vaccination programme, particularly among incompletely-vaccinated infants.

This was a population-based, prospective, nationwide active IPD surveillance study in Israel, 2004–2019, in children < 24 months old. We estimated annual incidence rates (IR) of overall IPD, IPD caused by PCV13 serotypes (VT13), and non-PCV13 serotypes (NVT13). Annual IPD IRs were stratified by age: < 4 months (receiving ≤ 1 dose), 4–6 months (immediately post dose 2), 7–12 months (a few months post dose 2), and 13–23 months (post dose 3). Late-PCV (2004–2008) to pre-PCV13 (2016–2019) mean annual IR ratios (IRRs) were calculated.

2,569 IPD episodes were recorded. VT13 decreased > 90% in all age groups, while NVT13 seemed to increase. All-IPD rates declined in all age groups by 56–70%. The 2+1 schedule impact on 7–12-month-old infants (pre-booster) was similar to that on 13–23-month-old children (post booster), with PCV13 IPD reductions of 97% and 98%, respectively.

Indirect (herd) protection of infants, including < 4 month-olds with ≤ 1 PCV dose, was achieved by the 2+1 PCV schedule programme which thus seems adequate.

Central line-associated bloodstream infection (CLABSI) is among the most common preventable infectious complications in patients in intensive care units (ICU). In 2011, the Israel National Center for Infection Control initiated a nationwide CLABSI prevention programme.

To evaluate the impact of different components of the programme on CLABSI and non-CLABSI rates in medical-surgical ICUs.

We included data collected from all 29 medical-surgical ICUs in Israel from November 2011 to December 2019. The study period was divided into three phases: I (baseline, initial CLABSI prevention guidelines introduced, initial feedback on rates provided), II (initial guidelines widely implemented, surveillance undertaken, feedback continued) and III (after implementation of additional prevention measures). Interrupted time series analysis was used to compare CLABSI and non-CLABSI rates during the three phases.

The pooled mean (SD) incidence of CLABSI per 1,000 central line-days dropped from 7.4 (0.38) in phase I to 2.1 (0.13) in phase III (p < 0.001). The incidence rate ratio (IRR) was 0.63 (95% CI: 0.51–0.79) between phases I and II, and 0.78 (95% CI: 0.59–1.02) between phases II and III. The pooled mean (SD) incidence of non-CLABSI per 1,000 patient-days declined from 5.3 (0.24) in phase I to 3.4 (0.13) in phase III (p < 0.001).

National CLABSI prevention guidelines, surveillance and feedback resulted in significant reductions in CLABSI and non-CLABSI rates. In the wake of further interventions, significant reduction was achieved in ICUs reporting improvement in the uptake of additional prevention measures.

Surveillance of SARS-CoV-2 in wastewater offers a near real-time tool to track circulation of SARS-CoV-2 at a local scale. However, individual measurements of SARS-CoV-2 in sewage are noisy, inherently variable and can be left-censored.

We aimed to infer latent virus loads in a comprehensive sewage surveillance programme that includes all sewage treatment plants (STPs) in the Netherlands and covers 99.6% of the Dutch population.

We applied a multilevel Bayesian penalised spline model to estimate time- and STP-specific virus loads based on water flow-adjusted SARS-CoV-2 qRT-PCR data for one to four sewage samples per week for each of the more than 300 STPs.

The model captured the epidemic upsurges and downturns in the Netherlands, despite substantial day-to-day variation in the measurements. Estimated STP virus loads varied by more than two orders of magnitude, from ca 10¹² virus particles per 100,000 persons per day in the epidemic trough in August 2020 to almost 10¹⁵ per 100,000 in many STPs in January 2022. The timing of epidemics at the local level was slightly shifted between STPs and municipalities, which resulted in less pronounced peaks and troughs at the national level.

Although substantial day-to-day variation is observed in virus load measurements, wastewater-based surveillance of SARS-CoV-2 that is performed at high sampling frequency can track long-term progression of an epidemic at a local scale in near real time.

The risk of SARS-CoV-2 (re-)infection remains present given waning of vaccine-induced and infection-acquired immunity, and ongoing circulation of new variants.

To develop a method that predicts virus neutralisation and disease protection based on variant-specific antibody measurements to SARS-CoV-2 antigens.

To correlate antibody and neutralisation titres, we collected 304 serum samples from individuals with either vaccine-induced or infection-acquired SARS-CoV-2 immunity. Using the association between antibody and neutralisation titres, we developed a prediction model for SARS-CoV-2-specific neutralisation titres. From predicted neutralising titres, we inferred protection estimates to symptomatic and severe COVID-19 using previously described relationships between neutralisation titres and protection estimates. We estimated population immunity in a French longitudinal cohort of 905 individuals followed from April 2020 to November 2021.

We demonstrated a strong correlation between anti-SARS-CoV-2 antibodies measured using a low cost high-throughput assay and antibody response capacity to neutralise live virus. Participants with a single vaccination or immunity caused by infection were especially vulnerable to symptomatic or severe COVID-19. While the median reduced risk of COVID-19 from Delta variant infection in participants with three vaccinations was 96% (IQR: 94–98), median reduced risk among participants with infection-acquired immunity was only 42% (IQR: 22–66).

Our results are consistent with data from vaccine effectiveness studies, indicating the robustness of our approach. Our multiplex serological assay can be readily adapted to study new variants and provides a framework for development of an assay that would include protection estimates.