Health care workers' influenza vaccination: motivations and mandatory mask policy

BACKGROUND: Vaccination of health care workers (HCW) against seasonal influenza (SI) is recommended but vaccination rate rarely reach >30%. Vaccination coverage against 2009 pandemic influenza (PI) was 52% in our hospital, whilst a new policy requiring unvaccinated HCW to wear a mask during patient care duties was enforced. AIMS: To investigate the determinants of this higher vaccination acceptance for PI and to look for an association with the new mask-wearing policy. METHODS: A retrospective cohort study, involving HCW of three critical departments of a 1023-bed, tertiary-care university hospital in Switzerland. Self-reported 2009-10 SI and 2009 PI vaccination statuses, reasons and demographic data were collected through a literature-based questionnaire. Descriptive statistics, uni- and multivariate analyses were then performed. RESULTS: There were 472 respondents with a response rate of 54%. Self-reported vaccination acceptance was 64% for PI and 53% for SI. PI vaccination acceptance was associated with being vaccinated against SI (OR 9.5; 95% CI 5.5-16.4), being a physician (OR 7.7; 95% CI 3.1-19.1) and feeling uncomfortable wearing a mask (OR 1.7; 95% CI 1.0-2.8). Main motives for refusing vaccination were: preference for wearing a surgical mask (80% for PI, not applicable for SI) and concerns about vaccine safety (64%, 50%) and efficacy (44%, 35%). CONCLUSIONS: The new mask-wearing policy was a motivation for vaccination but also offered an alternative to non-compliant HCW. Concerns about vaccine safety and efficiency and self-interest of health care workers are still main determinants for influenza vaccination acceptance. Better incentives are needed to encourage vaccination amongst non-physician HCW.

The Association of H1N1 Pandemic Influenza with Congenital Anomaly Prevalence in Europe: An Ecological Time Series Study.

BACKGROUND: In the context of the European Surveillance of Congenital Anomalies (EUROCAT) surveillance response to the 2009 influenza pandemic, we sought to establish whether there was a detectable increase of congenital anomaly prevalence among pregnancies exposed to influenza seasons in general, and whether any increase was greater during the 2009 pandemic than during other seasons. METHODS: We performed an ecologic time series analysis based on 26,967 pregnancies with nonchromosomal congenital anomaly conceived from January 2007 to March 2011, reported by 15 EUROCAT registries. Analysis was performed for EUROCAT-defined anomaly subgroups, divided by whether there was a prior hypothesis of association with influenza. Influenza season exposure was based on World Health Organization data. Prevalence rate ratios were calculated comparing pregnancies exposed to influenza season during the congenital anomaly-specific critical period for embryo-fetal development to nonexposed pregnancies. RESULTS: There was no evidence for an increased overall prevalence of congenital anomalies among pregnancies exposed to influenza season. We detected an increased prevalence of ventricular septal defect and tricuspid atresia and stenosis during pandemic influenza season 2009, but not during 2007-2011 influenza seasons. For congenital anomalies, where there was no prior hypothesis, the prevalence of tetralogy of Fallot was strongly reduced during influenza seasons. CONCLUSIONS: Our data do not suggest an overall association of pandemic or seasonal influenza with congenital anomaly prevalence. One interpretation is that apparent influenza effects found in previous individual-based studies were confounded by or interacting with other risk factors. The associations of heart anomalies with pandemic influenza could be strain specific.

Differences in pandemic influenza vaccination policies for pregnant women in Europe.

BACKGROUND: An important component of the policy to deal with the H1N1 pandemic in 2009 was to develop and implement vaccination. Since pregnant women were found to be at particular risk of severe morbidity and mortality, the World Health Organization and the European Centers for Disease Control advised vaccinating pregnant women, regardless of trimester of pregnancy. This study reports a survey of vaccination policies for pregnant women in European countries. METHODS: Questionnaires were sent to European competent authorities of 27 countries via the European Medicines Agency and to leaders of registries of European Surveillance of Congenital Anomalies in 21 countries. RESULTS: Replies were received for 24 out of 32 European countries of which 20 had an official pandemic vaccination policy. These 20 countries all had a policy targeting pregnant women. For two of the four countries without official pandemic vaccination policies, some vaccination of pregnant women took place. In 12 out of 20 countries the policy was to vaccinate only second and third trimester pregnant women and in 8 out of 20 countries the policy was to vaccinate pregnant women regardless of trimester of pregnancy. Seven different vaccines were used for pregnant women, of which four contained adjuvants. Few countries had mechanisms to monitor the number of vaccinations given specifically to pregnant women over time. Vaccination uptake varied. CONCLUSIONS: Differences in pandemic vaccination policy and practice might relate to variation in perception of vaccine efficacy and safety, operational issues related to vaccine manufacturing and procurement, and vaccination campaign systems. Increased monitoring of pandemic influenza vaccine coverage of pregnant women is recommended to enable evaluation of the vaccine safety in pregnancy and pandemic vaccination campaign effectiveness.

The Proteolytic Activation of (H3N2) Influenza A Virus Hemagglutinin Is Facilitated by Different Type II Transmembrane Serine Proteases.

UNLABELLED: Cleavage of influenza virus hemagglutinin (HA) by host cell proteases is necessary for viral activation and infectivity. In humans and mice, members of the type II transmembrane protease family (TTSP), e.g., TMPRSS2, TMPRSS4, and TMPRSS11d (HAT), have been shown to cleave influenza virus HA for viral activation and infectivityin vitro Recently, we reported that inactivation of a single HA-activating protease gene,Tmprss2, in knockout mice inhibits the spread of H1N1 influenza viruses. However, after infection ofTmprss2knockout mice with an H3N2 influenza virus, only a slight increase in survival was observed, and mice still lost body weight. In this study, we investigated an additional trypsin-like protease, TMPRSS4. Both TMPRSS2 and TMPRSS4 are expressed in the same cell types of the mouse lung. Deletion ofTmprss4alone in knockout mice does not protect them from body weight loss and death upon infection with H3N2 influenza virus. In contrast,Tmprss2(-/-)Tmprss4(-/-)double-knockout mice showed a remarkably reduced virus spread and lung pathology, in addition to reduced body weight loss and mortality. Thus, our results identified TMPRSS4 as a second host cell protease that, in addition to TMPRSS2, is able to activate the HA of H3N2 influenza virusin vivo IMPORTANCE: Influenza epidemics and recurring pandemics are responsible for significant global morbidity and mortality. Due to high variability of the virus genome, resistance to available antiviral drugs is frequently observed, and new targets for treatment of influenza are needed. Host cell factors essential for processing of the virus hemagglutinin represent very suitable drug targets because the virus is dependent on these host factors for replication. We reported previously thatTmprss2-deficient mice are protected against H1N1 virus infections, but only marginal protection against H3N2 virus infections was observed. Here we show that deletion of two host protease genes,Tmprss2andTmprss4, strongly reduced viral spread as well as lung pathology and resulted in increased survival after H3N2 virus infection. Thus, TMPRSS4 represents another host cell factor that is involved in cleavage activation of H3N2 influenza virusesin vivo.