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Vaccine Safety For Clinicians: It takes about six months for the manufacturers to formulate and produce the millions of doses required to deal with the seasonal epidemics; occasionally, a new or overlooked strain becomes prominent during that time. Infektiöse Bursitis, Infectious Bursal Disease, Avian Nephrosis Die Gumboro Krankheit ist eine der am häufigsten vorkommenden viralen Erkrankungen bei Küken, sie kommt weltweit vor, ist wirtsspezifisch und hochkontagiös.

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Beyond week 8, mortality increased more gradually in all groups. Mortality deaths per person-years by week after influenza vaccination among higher-risk vaccinees, lower-risk vaccinees, and all vaccinees 1. The flat reference line shows the average monthly mortality during all unvaccinated time in the study population. COPD, chronic obstructive pulmonary disease. The vaccination-mortality association throughout the flu year is shown in Figure 5. The triangles show the proportion vaccinated among decedents by week of death, omitting the deaths that occurred when the influenza virus was circulating.

The proportion of decedents who were vaccinated was always lower than expected, where the proportion expected comes from vaccine coverage in the decedent's age-sex group on the day of death as described above. Observed and expected proportions of decedents with influenza vaccination and the corresponding bias in vaccine effectiveness VE , Kaiser Permanente, Northern California, — A smoothed estimate of this trajectory—smoothed by means of case-centered logistic regression—is our point of departure for differentiating vaccine effectiveness from bias.

VE estimates and confidence intervals are shown in Table 2 , after adjustment for the bias. Vaccine effectiveness against all-cause mortality during flu season was 4. Vaccination appears to have been more effective 5. In addition, the vaccine appears to have been more effective against mortality from cardiovascular and respiratory causes 8.

The analysis of excess flu-attributable mortality yielded results consistent with our inference that vaccine effectiveness is the reason why the arrival of influenza strengthened the vaccination-mortality association: During flu season, mortality was higher by 7. We found that flu shots reduced all-cause mortality among elderly Kaiser Permanente members by 4. Other researchers have reported that flu shots reduce mortality by much greater amounts. In a meta-analysis of results from 20 cohort and case-control studies, Voordouw et al.

However, Simonsen et al. Our estimate of excess mortality during flu season was 7. This excess mortality of 7. Our findings suggest that had none of the elderly been vaccinated, excess mortality during flu season would have averaged about 9.

We infer that our 4. Mortality in the Kaiser Permanente elderly population was approximately 3, per , person-years Table 1. On average, of these 3, deaths occurred during a laboratory-defined flu season, including deaths in vaccinees. Our VE estimate of 4. Before estimating vaccine effectiveness, our initial goal was to examine who gets flu shots. Whereas Nichol et al. We found a curvilinear relation between predictors of mortality and vaccination.

Perhaps other investigators overlooked the curvilinearity because they considered mainly dichotomous indicators of risk. In our population, as in Nichol et al.

However, most patients with these conditions had only a moderately elevated risk of death, often in the range where vaccine coverage was highest.

In higher-risk patients, who drive mortality rates in the upcoming flu season, the propensity to obtain flu shots waned. However, until then, patients with chronic conditions have more reason and opportunity to get vaccinated than healthy people, because patients with chronic conditions tend to be more vulnerable to influenza and have more contact with providers who encourage vaccination. Within low-risk subgroups as well as high-risk subgroups, mortality was low soon after vaccination and then increased over time in a pattern suggesting selection bias Figure 4.

It is this rise in mortality with time since vaccination that is especially challenging in the estimation of vaccine effectiveness. One strategy is to strive for better measures of frailty for covariate adjustment and for exclusion of patients known to be near death at the outset of the autumn vaccination campaign.

We traced the trajectory of the bias over time and compared the vaccination-mortality association inside flu season with that outside of flu season. What facilitated this approach was: The potential confounders of our VE estimate are not the unmeasured aspects of frailty which confounded Nichol et al.

We examined the difference in differences using case-centered logistic regression. Case-centered logistic regression has several noteworthy features. First, it is closely related to Cox regression in a cohort study. It is equivalent to a stratified Cox model in which death is regressed on a time-varying indicator of vaccination.

Each record in the case-centered model summarizes an entire risk set in the corresponding Cox model. Second, case-centered logistic regression is closely related to matched case-control studies with risk set sampling also called incidence density sampling. However, there is no sampling: Data are used from all available controls. Third, it simplifies the analysis of changes in the exposure-outcome relation. In effect, it makes the odds ratio the dependent variable, which is then examined in relation to time and other factors.

Fourth, case-centered logistic regression reduces computational burdens dramatically. These can be daunting in large studies with time-varying exposures.

Fifth, it can minimize privacy concerns in a multisite study. Researchers at the study sites only need to pool aggregated data about each risk set rather than personal data about each person.

Our data and findings have limitations. First, we were missing data on flu shots given outside of Kaiser Permanente if they were never reported to Kaiser Permanente. If we missed flu shots delivered in nursing homes to patients near death, then we exaggerated the bias that we highlighted.

Second, Kaiser Permanente's elderly population may differ from other elderly populations. Care-seeking behavior near the end of life may vary across sociocultural settings, and vaccination outreach may vary across practice settings. Third, our VE estimate was conditional on the severity of the flu seasons and the match of the vaccines to circulating strains of the virus. Fourth, we overlooked herd effects.

Fifth, we overlooked late effects if the vaccine prevents complications that increase mortality after flu season. The lower bound 0. Seventh, our focus on mortality overlooked the impact of vaccination on morbidity. All-cause mortality is nonspecific.

Nevertheless, it is important to consider, especially in the elderly. For example, Lymphocyte T-Cell Immune Modulator inhibits viral growth in the murine model of influenza. Influenza infects many animal species, and transfer of viral strains between species can occur.

Birds are thought to be the main animal reservoirs of influenza viruses. All known subtypes HxNy are found in birds, but many subtypes are endemic in humans, dogs , horses , and pigs ; populations of camels , ferrets , cats , seals , mink , and whales also show evidence of prior infection or exposure to influenza. The main variants named using this convention are: Cat flu generally refers to feline viral rhinotracheitis or feline calicivirus and not infection from an influenza virus.

In pigs, horses and dogs, influenza symptoms are similar to humans, with cough, fever and loss of appetite. These vaccines can be effective against multiple strains and are used either as part of a preventative strategy, or combined with culling in attempts to eradicate outbreaks.

Flu symptoms in birds are variable and can be unspecific. Some strains such as Asian H9N2 are highly virulent to poultry and may cause more extreme symptoms and significant mortality. An avian-adapted, highly pathogenic strain of H5N1 called HPAI A H5N1 , for "highly pathogenic avian influenza virus of type A of subtype H5N1" causes H5N1 flu , commonly known as "avian influenza" or simply "bird flu", and is endemic in many bird populations, especially in Southeast Asia. It is epizootic an epidemic in non-humans and panzootic a disease affecting animals of many species, especially over a wide area , killing tens of millions of birds and spurring the culling of hundreds of millions of other birds in an attempt to control its spread.

Most references in the media to "bird flu" and most references to H5N1 are about this specific strain. In almost all cases, those infected have had extensive physical contact with infected birds. The exact changes that are required for this to happen are not well understood. In March , the Chinese government reported three cases of H7N9 influenza infections in humans. Two of whom had died and the third was critically ill.

Although the strain of the virus is not thought to spread efficiently between humans, [] [] by mid-April, at least 82 persons had become ill from H7N9, of which 17 had died.

These cases include three small family clusters in Shanghai and one cluster between a neighboring girl and boy in Beijing, raising at least the possibility of human-to-human transmission. WHO points out that one cluster did not have two of the cases lab confirmed and further points out, as a matter of baseline information, that some viruses are able to cause limited human-to-human transmission under conditions of close contact but are not transmissible enough to cause large community outbreaks.

In pigs swine influenza produces fever, lethargy, sneezing, coughing, difficulty breathing and decreased appetite. Although mortality is usually low, the virus can produce weight loss and poor growth, causing economic loss to farmers. In all, 50 human cases are known to have occurred since the virus was identified in the midth century, which have resulted in six deaths. In , a swine-origin H1N1 virus strain commonly referred to as "swine flu" caused the flu pandemic , but there is no evidence that it is endemic to pigs i.

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Morbidity and Mortality Weekly Report. Archived PDF from the original on 21 July Archived from the original on 19 June Cleve Clin J Med. Communicating the Risk" PDF. Perspectives in Health Magazine. Archived PDF from the original on 21 January Published 26 August This distinction is not so clear within the schools of physiotherapy and nursing where students undertake health service placements and campus based studies in each year. Eligibility for federal government-funded vaccines and the contraindications to influenza vaccine were defined in the survey according to the Australian Immunisation Handbook.

Proportional weights were applied Medicine 0. The survey was open for 6 wk and non-responders were followed up with 3 repeat invitations during this time.

Qualitative data on the enablers and barriers were gathered through semi-structured interviews with 2 students 1 vaccinated, 1 not vaccinated from each year group, of each school to a total of 22 students. These were selected at random from survey respondents who had volunteered to be interviewed. Interviews were recorded and transcribed before being analyzed for themes.

Free and informed consent was gained from all subjects who participated. National Center for Biotechnology Information , U. Journal List Hum Vaccin Immunother v. Published online May 8. Uptake, barriers, and enablers among student health care providers at the University of Notre Dame Australia, Fremantle.

Author information Article notes Copyright and License information Disclaimer. David A Kelly, Email: Abstract Despite national and international recommendations, annual influenza vaccination uptake among health care providers HCPs remains sub-optimal. Introduction Influenza remains a significant burden to the Australian health care system. Results Online survey An amount of students Demographic characteristics of the student HCP population, survey respondents, and weighted univariate chi-square results for control variables, with the likelihood of having the influenza vaccination as the dependent variable.

Open in a separate window. Disclosure of Potential Conflicts of Interest No potential conflicts of interest were disclosed. Funding Source There was no external funding source. Influenza-attributable mortality in Australians aged more than 50 years: Fact Sheet no World Health Organization, National Health and Medical Research Group. The Australian Immunisation Handbook. Department of Health and Aging; A meta-analysis of effectiveness of influenza vaccine in persons aged 65 years and over living in the community.