Higher risk of SARS-CoV-2 Omicron BA.4/5 infection than of BA.2 infection after previous BA.1 infection, the Netherlands, 2 May to 24 July 2022.

BackgroundIn summer 2022, SARS-CoV-2 Omicron BA.5 became dominant in Europe. In vitro studies have shown a large reduction of antibody neutralisation for this variant.AimWe aimed to investigate differences in protection from previous infection and/or vaccination against infection with Omicron BA.4/5 vs BA.2.MethodsWe employed a case-only approach including positive PCR tests from community testing between 2 May and 24 July 2022 that were tested for S gene target failure (SGTF), which distinguishes BA.4/5 from BA.2 infection. Previous infections were categorised by variant using whole genome sequencing or SGTF. We estimated by logistic regression the association of SGTF with vaccination and/or previous infection, and of SGTF of the current infection with the variant of the previous infection, adjusting for testing week, age group and sex.ResultsThe percentage of registered previous SARS-CoV-2 infections was higher among 19,836 persons infected with Omicron BA.4/5 than among 7,052 persons infected with BA.2 (31.3% vs 20.0%). Adjusting for testing week, age group and sex, the adjusted odds ratio (aOR) was 1.4 (95% CI: 1.3-1.5). The distribution of vaccination status did not differ for BA.4/5 vs BA.2 infections (aOR = 1.1 for primary and booster vaccination). Among persons with a previous infection, those currently infected with BA4/5 had a shorter interval between infections, and the previous infection was more often caused by BA.1, compared with those currently infected with BA.2 (aOR = 1.9; 95% CI: 1.5-2.6).ConclusionOur results suggest immunity induced by BA.1 is less effective against BA.4/5 infection than against BA.2 infection.

Potential of ESBL-producing Escherichia coli selection in bovine feces after intramammary administration of first generation cephalosporins using in vitro experiments.

Selection and spread of Extended Spectrum Beta-Lactamase (ESBL) -producing Enterobacteriaceae within animal production systems and potential spillover to humans is a major concern. Intramammary treatment of dairy cows with first-generation cephalosporins is a common practice and potentially selects for ESBL-producing Enterobacteriaceae, although it is unknown whether this really occurs in the bovine fecal environment. We aimed to study the potential effects of intramammary application of cephapirin (CP) and cefalonium (CL) to select for ESBL-producing Escherichia coli in the intestinal content of treated dairy cows and in manure slurry, using in vitro competition experiments with ESBL and non-ESBL E. coli isolates. No selection of ESBL-producing E. coli was observed at or below concentrations of 0.8 µg/ml and 4.0 µg/ml in bovine feces for CP and CL, respectively, and at or below 8.0 µg/ml and 4.0 µg/ml, respectively, in manure slurry. We calculated that the maximum concentration of CP and CL after intramammary treatment with commercial products will not exceed 0.29 µg/ml in feces and 0.03 µg/ml in manure slurry. Therefore, the results of this study did not find evidence supporting the selection of ESBL-producing E. coli in bovine feces or in manure slurry after intramammary use of commercial CP or CL-containing products.