Effectiveness of the BNT162b2 mRNA Covid-19 vaccine in Spanish healthcare workers

INTRODUCTION

Frontline health care workers (HCW) have higher risk than the general population to become infected by SARS.CoV.2, so they were a priority group for Covid-19 vaccine administration. We compared the incidence and prevalence of HCW infected pre-and post-vaccination with the BNT162b2 mRNA COVID-19 vaccine.

MATERIAL AND METHODS

Prospective observational study carried out between 01/12/20 and 07/03/21 in La Paz University Hospital, Madrid (Spain). SARS.CoV.2 positive cases in HCW after vaccination were collected and compared to those hospitalized COVID-19 patients at the same hospital.

RESULTS

Two weeks after finishing the first round of vaccinations daily new cases of HCW infections (symptomatic and asymptomatic) decreased substantially and cumulative cases of infected HCW and hospitalized COVID-19 patients started to diverge. No new positive cases of HCW infection were registered seven days after the second dose of BNT162b2 mRNA COVID-19 vaccine.

CONCLUSIONS

BNT162b2 mRNA COVID-19 vaccine is highly effective in Spanish HCW.

Clinical characteristics and outcome of hospitalized elderly patients with COVID- 19 after vaccine failure

We described clinical characteristics and outcome of 160 patients over 65 years (01 September to 31 August 2021) who had a first positive SARS-CoV-2 PCR- test more than 14 days after full vaccination and were hospitalized with COVID-19. Median age of included patients was 84 years, 61.2% were over 80 years; 50.6% were male and most (82.5%) has at least one comorbidity. Up to 84% received specific treatment against COVID-19, including 76.9% low-flow oxygen therapy. We found that overall mortality was 25.6% and 30.6% in those older than 80 years. A higher mortality was significantly associated with older age and treatment with tocilizumab. Our data showed that although COVID-19 vaccines continue protecting elderly patients against hospitalization and death and might improve the prognosis after hospitalization in patients with breakthrough infections, mortality in this population -especially in those older than 80 years- remains very high.

Dissemination of a single ST11 clone of OXA-48-producing Klebsiella pneumoniae within a large polyclonal hospital outbreak determined by genomic sequencing

The population structure of a set of OXA-48-producing Klebsiella pneumoniae isolates belonging to sequence type 11 (ST11 Kp-OXA) and obtained from two hospitals in Madrid in the period from 2012 to 2015 was studied by genome sequencing. Overall, 97 ST11 Kp-OXA isolates were sequenced and their population structure and demography were studied by Bayesian phylodynamic analysis using core-genome SNVs. In total, 92 isolates were from Hospital La Paz, 57 of them from two selected units. The remaining five isolates were from different units of Hospital Doce de Octubre. Altogether, 96 out of the 97 ST11 Kp-OXA isolates could be ascribed to a single lineage that evolved into three sublineages. Demographic inference showed an expansion of the ST11 Kp-OXA in the first half of 2013 in agreement with the registered incidences. Dated phylogeny showed transmission clusters within hospital wards, between wards and between hospitals. The ST11 Kp-OXA outbreak in Hospital La Paz was largely due to the expansion of a single clone that was transmitted between different units and to Hospital Doce de Octubre. This clone diverged into three sub-lineages and spread out following a mixed mode of neutral core-genome evolution with some features of antibiotic selection, frequent large deletions and plasmid loss and gain events.

Effectiveness of the BNT162b2 mRNA Covid-19 vaccine in Spanish healthcare workers

INTRODUCTION

Frontline health care workers (HCW) have higher risk than the general population to become infected by SARS.CoV.2, so they were a priority group for Covid-19 vaccine administration. We compared the incidence and prevalence of HCW infected pre-and post-vaccination with the BNT162b2 mRNA COVID-19 vaccine.

MATERIAL AND METHODS

Prospective observational study carried out between 01/12/20 and 07/03/21 in La Paz University Hospital, Madrid (Spain). SARS.CoV.2 positive cases in HCW after vaccination were collected and compared to those hospitalized COVID-19 patients at the same hospital.

RESULTS

Two weeks after finishing the first round of vaccinations daily new cases of HCW infections (symptomatic and asymptomatic) decreased substantially and cumulative cases of infected HCW and hospitalized COVID-19 patients started to diverge. No new positive cases of HCW infection were registered seven days after the second dose of BNT162b2 mRNA COVID-19 vaccine.

CONCLUSIONS

BNT162b2 mRNA COVID-19 vaccine is highly effective in Spanish HCW.

Population structure of OXA-48-producing Klebsiella pneumoniae ST405 isolates during a hospital outbreak characterised by genomic typing

OBJECTIVES

The aim of this study was to investigate the structure of a broad and sustained hospital outbreak of OXA-48-producing Klebsiella pneumoniae (KpO48) belonging to sequence type 405 (ST405).

METHODS

Whole-genome sequencing and comparison of ten ST405 KpO48 isolates obtained from clinical samples in our hospital was performed. Using stringent criteria, 36 single nucleotide polymorphisms (SNPs) were detected (range 0-21 in pairwise comparisons), and allele-specific PCR was used to call the SNPs among a larger set of isolates.

RESULTS

Several haplotypes were identified within the population. The haplotypes did not show a spatial structure, but a temporal evolution of sequential haplotype replacements was observed.

CONCLUSIONS

The dispersed spatial distribution suggests a reservoir formed by a large pool of colonised patients, and the temporal replacement pattern suggests that the sustained outbreak was composed of several small outbreaks that appeared and rapidly dispersed to several units.

Successful control of 2 simultaneous outbreaks of OXA-48 carbapenemase-producing Enterobacteriaceae and multidrug-resistant Acinetobacter baumannii in an intensive care unit

BACKGROUND

This report describes a double outbreak of OXA-48-producing Enterobacteriaceae (OXA-48-PE) and multidrug-resistant Acinetobacter baumannii (MRAB) in an intensive care unit (ICU) and the effectiveness of measures implemented, including decontamination with vaporized hydrogen peroxide (VHP).

METHODS

Affected patients were isolated in a confined area and cared for by dedicated personnel. Four percent chlorhexidine soap was used for patient daily hygiene. All patients are subjected to contact precautions. An in-depth cleaning of the ICU was performed with a chlorine solution, followed by decontamination with VHP. Environmental samples were taken before and after the decontamination.

RESULTS

From July-October 2015, 13 patients were colonized or infected by OXA-48-PE and 18 by MRAB in the ICU. The cumulative incidence of OXA-48-PE and MRAB was 3.48% and 4.81%, respectively. In the period after the intervention, they were 0.8% and 0%, respectively (P < .001). Before the VHP biodecontamination, 4.5% of environmental samples were positive for OXA-48-PE and none for MRAB. After biodecontamination, 1.4% of samples were positive for OXA-48-PE.

CONCLUSIONS

This study emphasizes the importance of environmental hygiene in the control of outbreaks caused by microorganisms of high environmental impact. The rapid effect after the VHP treatment suggests an influence of this measure in eradication.

Microbial competition in environmental nosocomial reservoirs and diffusion capacity of OXA48-Klebsiella pneumoniae: potential impact on patients and possible control methods

BACKGROUND

We have found clusters of Klebsiella pneumoniae with OXA48-carbepenemase cases in some hospital rooms, and decided to investigate whether bathroom siphons could be a reservoir for OXA48 bacteria, as occurs with K. oxytoca with other types of carbepenemases.

METHODS

We evaluated the microbial competition between strains with OXA48 and VIM carbepenemases, in diluted nutrient-broth, on a slime germ-carrier. We compared the number of colonies at 5 and 10 days on the contaminated carriers with one or two strains. We evaluated the dissemination of K. pneumoniae with carbepenemase OXA48 or VIM from thumbs and index fingers of volunteers, to standard surfaces (20 glass germ-carrier by each volunteer). After, we counted the number of microorganisms on each carrier. Microbiological weekly studies of faecal microbiota of all patients were obtained in Traumatology and Oncology. Moreover, we studied samples of the sink in their rooms. PCR and MLST sequence-type was determined in all K. pneumoniae diagnosed from patients and sinks.

RESULTS

A large possibility of diffusion from contaminated hands, which continue to transmit high numbers of microorganisms after more than 10 successive surface contacts, was highlighted; OXA bacteria were more persistent than VIM bacteria. Microbial competition studies showed that VIM bacteria are inhibited by OXA ones. These observations can explain the concentration of cases of K. pneumoniae OXA48 in some rooms in Traumatology and Oncology, producing a significant OR between rooms with OXA48-bacteria-contaminated siphons and other rooms (3.1 and 3.3 respectively). Risk was lowered after changing or disinfecting (heat plus chlorinated disinfectant) the contaminated siphons. Siphon colonization by VIM bacteria was not related with human infections by similar microorganisms.

CONCLUSIONS

Bathroom siphons can be a reservoir for K. pneumoniae OXA48 and lead to outbreaks. Outbreaks can be controlled by replacement or heat plus chemical treatment of the sink-siphons.

[Nosocomial outbreak of epidemic keratoconjunctivitis in a neonatal intensive care unit]

OBJECTIVE

To describe an epidemic nosocomial outbreak of keratoconjunctivitis affecting at least 43 people in a Neonatal Intensive Care Unit in Madrid, between May and October 2002, perform epidemiologic research and determine preventive measures to prevent new outbreaks.

METHODS

Description of the outbreak, clinical case definition, microbiologic and epidemiologic research through the use of questionnaires. Analysis of the incidence of subepithelial infiltrates 1 year after infection and the use of topical corticosteroid therapy.

RESULTS

The epidemic began in the Neonatal Service, with a pair of twins being found as the initial focus. Dissemination occurred to about 24 workers of the unit, and 19 workers from other services. The microbiologic diagnosis confirmed adenovirus in 10 conjunctival smears and one serologically, with the remainder obeying clinical and epidemiological criteria of such infection. Infected patients using topical corticosteroids had a higher incidence of infiltrates 12 months later than those not using such agents (p=0.003 in Fisher test).

CONCLUSIONS

Epidemic keratoconjunctivitis occurs frequently, is highly contagious and has possible long-term sequelae, necessitating the use of preventive measures to avoid spread and new outbreaks.