Efficacy of influenza vaccine among geriatric inpatients: effect of previous vaccination and antibody induction by single and twice injections

To investigate the effect of previous influenza vaccination and the difference in antibody induction by single and twice injection of influenza vaccine in the elderly, hemagglutination inhibition (HI) antibody titers of the three types of influenza viruses were measured. Influenza vaccination was done for 217 inpatients. For the patients who had influenza vaccination in the year prior to the study, influenza vaccine was administered once to 77 patients and twice to another 70 patients. Influenza vaccine was injected twice to 70 patients who had not received influenza vaccine in the previous years. The influenza vaccine induced an increase in HI titer in almost all patients. The geometric mean of the HI titer and the frequency of patients with HI titers over 128x were similar after vaccination in the groups of patients who were injected twice, irrespective of whether or not influenza vaccination was given in the year prior to the study. The geometric means of the HI titers for influenzas A/H3N2 and B and the frequency of HI titers over 128x for influenza A/H3N2 after vaccination were lower in the patients who received vaccine once than in the patients vaccinated twice. These results suggest that prior vaccination does not diminish antibody response to influenza vaccine significantly in the elderly when influenza vaccine is injected twice. Although single injection is inferior to twice injection in antibody induction with some vaccine virus strains, induction of HI titers over 128x is found in more than 70% of elderly. Single injection of influenza vaccine may be practically effective and useful for protection of influenza infection in the elderly.     

Influenza virus vaccination and booster in B-cell chronic lymphocytic leukaemia patients

Background: Influenza vaccination is recommended for patients with B-cell chronic lymphocytic leukaemia (CLL). Because response rates are often low, we decided to evaluate antibody response to single and booster vaccinations with influenza A and B virus vaccine in these patients. Methods: Twenty patients with B-CLL received two subunit virus vaccine injections 21 days apart. Antibody titres were determined before and 21 days after the single and booster vaccinations. The serological response was expressed using the following criteria: (1) response rate, i.e. the proportion of subjects with at least a 4-fold titre increase; (2) the protection rate, i.e. the proportion of subjects exceeding the threshold of 100 (influenza A) or 200 (influenza B); and (3) the mean fold increase (MFI), i.e. the difference between the log-adjusted geometric mean titres of pre- and post-vaccination sera. Results: Response rates were 5% for influenza A and 15% for B after the single vaccination and 15% for A and 30% for B after the booster vaccination. Protection rates were 0% for influenza A and 25% for B after the single vaccination; they were 5% (H1N1) and 10% (H3N2) for influenza A and 30% for B after the booster. The MFI+/-S.D. (range) after the booster vaccination was 0.26+/-0.33 (0-1.00), 0.17+/-0.34 (0-1.00) and 0.35+/-0.34 (0-1.20) for H1N1, H3N2 and influenza B, respectively. Conclusion: In this study with B-CLL patients, immune response to influenza vaccination was poor. Thus, single and booster vaccinations with influenza virus vaccine do not appear to be of great value to patients with B-cell CLL.     

Influenza vaccine in the elderly and chronic obstructive pulmonary disease

Influenza viruses are RNA viruses that are a major determinant of morbidity and mortality caused by respiratory disease. Influenza is highly contagious and has caused epidemics and pandemics for centuries. Most influenza infections are selflimited, but lower respiratory tract and cardiac complications can result in increases in hospitalizations and deaths. The recommended composition of influenza vaccine is updated annually in order to provide a vaccine that is antigenically well matched with the new influenza virus strains that are expected to cause epidemics. Influenza vaccination significantly reduces mortality; however, approximately one third of elderly Americans are not immunized annually. The nation’s goal is to increase the influenza vaccination rate among the elderly to 90%. Vaccination is the most effective measure for reducing the impact of influenza and is a cost-effective preventive health intervention for the elderly and individuals with chronic obstructive pulmonary disease.     

Prevalence rate and reasons for refusals of influenza vaccine in elderly

More knowledge on the reasons for refusal of the influenza vaccine in elderly patients is essential to target groups for additional information, and hence improve coverage rate. The objective of the present study was to describe precisely the true motives for refusal. All patients aged over 64 who attended the Medical Outpatient Clinic, University of Lausanne, or their private practitioner's office during the 1999 and 2000 vaccination periods were included. Each patient was informed on influenza and its complications, as well as on the need for vaccination, its efficacy and adverse events. The vaccination was then proposed. In case of refusal, the reasons were investigated with an open question. Out of 1398 patients, 148 (12%) refused the vaccination. The main reasons for refusal were the perception of being in good health (16%), of not being susceptible to influenza (15%), of not having had the influenza vaccine in the past (15%), of having had a bad experience either personally or a relative (15%), and the uselessness of the vaccine (10%). Seventeen percent gave miscellaneous reasons and 12% no reason at all for refusal. Little epidemiological knowledge and resistance to change appear to be the major obstacles for wide acceptance of the vaccine by the elderly.     

Standing orders in an ambulatory setting increases influenza vaccine usage in older people

OBJECTIVES: To determine whether standing orders for influenza vaccine increase its usage in an ambulatory setting in elderly patients. DESIGN: Retrospective analysis of influenza vaccine usage over 4 years (1999-2002). SETTING: University ambulatory setting. PARTICIPANTS: Overall, 912 elderly patients of two physicians who issued standing orders and 884 elderly patients of two physicians who did not do so constituted the study group. MEASUREMENTS: Physicians were categorized as to whether they issued a verbal or written standing order to their nurses to administer the influenza vaccine to patients aged 65 and older. Rates of influenza vaccination of patients whose physicians used standing orders were compared with those of physicians who did not use standing orders. RESULTS: Five hundred seventy-six (63%) patients of physicians who used standing orders received influenza vaccine, compared with 332 (38%) patients of physicians who did not use them (P<.001). Standing orders accounted for a significantly higher rate of influenza vaccination in each study year. Moreover, in 2001, when influenza vaccine delivery was delayed, physicians who used standing orders maintained their same rate of usage, but physicians who did not had rates of about one-half their usage of the other 3 years. CONCLUSION: More Medicare recipients received influenza vaccine when their physicians used standing orders for its administration than when their physicians did not. Influenza vaccine represents an important prevention modality that demands widespread implementation, and standing orders can increase its usage.     

What is the role of virus vaccination in patients with asthma?

It is estimated that viruses play a role in 30% to 80% of asthma exacerbations. Thus, virus vaccination in patients with asthma could play an important role in preventing asthma exacerbations and other complications. Influenza is the only agent for which a routine vaccine is currently available. This article discusses whether influenza vaccination in patients with asthma, based on the available evidence, is justified. Cost-effectiveness of (influenza) vaccination for patients with asthma is questionable. For the other major viruses involved, the present state of affairs is described. Although progress is being made, a vaccine may be available in the near future only for respiratory syncytial virus (RSV). Meanwhile, clinicians and patients should aim for an optimal treatment with the currently available asthma medication.     

The effect of whole virus influenza vaccination on theophylline pharmacokinetics

The effect of whole virus influenza vaccination on theophylline pharmacokinetics was evaluated in 16 normal subjects. Because previous reports had suggested that influenza vaccine induces interferon production and may potentially depress hepatic metabolism of theophylline, serum interferon concentrations were monitored for 6 days after vaccination. Lymphocytes from 6 subjects were incubated in vitro with dilute whole virus vaccine (WVV) or dilute split virus vaccine (SVV) to assess their immunocompetence and the immunogenic potential of the 2 vaccine preparations. Additionally, influenza antibody response was monitored by prevaccination and postvaccination serum antibody titers in 11 subjects. No significant change in half-life, total body clearance, volume of distribution of maximal serum theophylline concentration compared to prevaccine values was observed at either 2 or 6 days after vaccination. No interferon production was detected in vivo up to 6 days after vaccination. In vitro lymphocyte interferon induction assay demonstrated mean interferon levels of 12,252 +/- 9,819 IU/ml for WVV and 888 +/- 1,180 IU/ml for SVV (p less than 0.05), demonstrating the immunocompetence of the subject's lymphocytes and confirming the greater immunogenic potential of WVV. Seven of 11 subjects (64%) showed a 4-fold rise in influenza antibody titer to at least one of the vaccine antigens. We conclude that whole virus influenza vaccine does not alter theophylline pharmacokinetics. In addition, it has greater immunogenic potential than split virus vaccine in vitro but does not induce significant interferon production in vivo. This study adds further evidence supporting the safety of the concomitant use of influenza vaccine in patients taking theophylline.(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute respiratory illness among immunized and nonimmunized patients with high-risk factors during a split season of influenza A and B

A prospective survey of acute respiratory illness (RI) was made among 329 vaccinated and unvaccinated ambulatory patients with high-risk factors for influenza. Surveillance for virus during the influenza season revealed the predominance of influenza A and B in sequential periods. During the influenza A period, febrile RI was greatest among patients with chronic pulmonary disease; among 66 patients, vaccination significantly reduced RI. Age greater than 65 y (199 patients) and heart (90 patients) and metabolic diseases (151 patients) did not increase the relative frequency of febrile RI, and vaccine administration caused no apparent reduction in frequency of RI. During the influenza B period, no differences in RI were observed between the groups, and the frequency of RI was unrelated to vaccination. Variability in virus and vaccine specificities may have been important. Except for one subset of specific virus and host conditions, no overall reduction in influenza-like or total RI was observed from vaccinating ambulatory, high-risk patients.     

Seasonal influenza vaccination in health-care workers: the influence of consultants on the uptake of vaccination by medical students and early career doctors

BackgroundThe Chief Medical Officer for England recommends that all health-care workers receive an influenza vaccination annually. Medical students are also encouraged to get vaccinated. High vaccination coverage is believed to be the best form of protection against the spread of influenza within hospital settings, protecting both staff and patients, and reducing virus transmission. However, uptake of seasonal influenza vaccination by health-care workers remains substantially lower than the target level of 75%. Our study aimed to provide a deeper insight into the influenza vaccination practices of health-care workers.MethodsAn opportunistic sampling strategy was used and participants recruited via compulsory teaching sessions. We conducted a series of semi-structured interviews with seven medical students and nine foundation doctors, to explore the factors informing their vaccination decisions. Interviews were transcribed and the data analysed thematically. Data collection and analysis took place as an iterative process, until theoretical saturation was achieved.FindingsOf the 16 participants, ten had been vaccinated during the 2015–16 season. A number of key themes emerged, and there were inconsistencies between an individual's opinion of the vaccine, their intentions, and their vaccination status. For example, someone reporting negative opinions of the vaccine could have been vaccinated. Moreover, individuals did not necessarily vaccinate year on year. Participants were influenced by senior staff as role models, demonstrating both positive and negative attitudes towards the vaccine. Participants often presented this observation in the context of their own conflicting ideals of medical professionalism. The decision making processes around influenza vaccination seem to be finely balanced, take place within a culture of relative ambivalence, and can easily be tipped one way or the other by factors such as convenience.InterpretationThe findings are drawn from a diverse sample, and are supported by the literature. This study suggests that senior staff have an important role in the vaccination practices of juniors. The influential role of consultants could be used as part of a future strategy to increase vaccination, since positive role models can facilitate a cultural shift in favour of vaccination uptake. Future research involving senior staff is necessary to understand the complexities behind their own vaccination practices.FundingColt Foundation.     

Unchanged bronchial reactivity after killed influenza virus vaccine in adult asthmatics

Polyvalent killed influenza virus vaccine or saline was administered subcutaneously to 27 asthmatics to investigate the effect of influenza vaccine on respiratory function and on airway responsiveness to inhaled histamine. The patients were adults with mild to moderate asthma. Airway resistance (Raw) and intrathoracic gas volume (ITGV) were measured immediately before and 2, 3 and 21 days after vaccine or saline injection. Raw and ITGV values were used to calculate specific airway conductance (SGaw). Bronchial reactivity was expressed as the provocative dose of histamine diphosphate producing a decrease of 40% in SGaw (PD40). Fourteen (87%) of 16 asthmatics who received killed virus vaccine displayed a significant rise in serum antibody level as measured by single radial haemolysis in gel test. No significant alterations in mean Raw, ITGV and SGaw values were observed after viral vaccination. The median PD40 values for histamine also remained unchanged. However, an increased bronchial reactivity was observed in some patients after administration of virus vaccine or saline. Subclinical natural infection or allergen exposure cannot be excluded as possible causes of the increased airway reactivity in these patients. The side-effects of vaccination were minimal and no more harmful than those produced by saline injection. We conclude that the killed influenza virus vaccine used is effective in boosting serum antibody levels and is suitable for adult asthmatics when prophylactic immunisation is indicated.     

Influenza Vaccination in Adults with Asthma: Safety of an Inactivated Trivalent Influenza Vaccine

Despite recommendations in most countries for giving inactivated influenza vaccine to people with asthma, only a minority currently receive it. One reason for low vaccine coverage has been concern that vaccination may induce exacerbations of asthma. In this randomized trial, 291 patients between 18 and 65 years of age received either an inactivated influenza vaccine followed 14 days later by a saline placebo or placebo followed by the vaccine. Each patient received 1 dose of vaccine and 1 dose of placebo. The percentage of patients reporting at least one asthma exacerbation within 14 days after injection was similar following vaccine or placebo (28.3% and 25.5%, respectively). The combined exacerbation rate during the first 14-day interval was higher (31.5%) than that during the second 14-day interval (22.4%, P = 0.0135), indicating that the occurrence of exacerbations was not likely to be related to the sequence of injections. The percentages of individuals with solicited systemic symptoms were 56.6% and 44.8% after vaccine or placebo injection, respectively. We conclude that influenza vaccination did not increase the incidence of asthma exacerbations compared to placebo in this study and the vaccine was well tolerated. The results thus support annual influenza vaccination in patients with asthma.     

Influenza Vaccination in Adults with Asthma: Safety of an Inactivated Trivalent Influenza Vaccine

Despite recommendations in most countries for giving inactivated influenza vaccine to people with asthma, only a minority currently receive it. One reason for low vaccine coverage has been concern that vaccination may induce exacerbations of asthma. In this randomized trial, 291 patients between 18 and 65 years of age received either an inactivated influenza vaccine followed 14 days later by a saline placebo or placebo followed by the vaccine. Each patient received 1 dose of vaccine and 1 dose of placebo. The percentage of patients reporting at least one asthma exacerbation within 14 days after injection was similar following vaccine or placebo (28.3% and 25.5%, respectively). The combined exacerbation rate during the first 14-day interval was higher (31.5%) than that during the second 14-day interval (22.4%, P = 0.0135), indicating that the occurrence of exacerbations was not likely to be related to the sequence of injections. The percentages of individuals with solicited systemic symptoms were 56.6% and 44.8% after vaccine or placebo injection, respectively. We conclude that influenza vaccination did not increase the incidence of asthma exacerbations compared to placebo in this study and the vaccine was well tolerated. The results thus support annual influenza vaccination in patients with asthma.     

Management of Influenza Virus Infections with Neuraminidase Inhibitors

Although influenza vaccination remains the primary method for the prevention of influenza, efficacy may be limited by a poor match between the vaccine and circulating strains and the poor response of elderly patients. Hence, there is an important role for antiviral therapy in the management of influenza. While amantadine and rimantadine have been available for the treatment of influenza in some countries for several years, they are only effective against influenza A viruses, they can have neurological and gastrointestinal adverse effects, and resistant virus is rapidly generated. Neuraminidase inhibitors, a new class of drug, are potent and specific inhibitors of all strains of influenza virus, and they have minimal adverse effects. The greatest benefit is seen in those patients presenting <30 hours after development of influenza symptoms, those with severe symptoms or those in high-risk groups. In addition to treatment of the infection, both drugs are effective prophylactically and have been shown to limit spread of infection in close communities, such as families and in nursing homes. No resistant virus strains have been isolated from normal individuals treated with zanamivir. Resistant virus can be isolated from approximately 1% of adults and 5% of paediatric patients with influenza treated with oseltamivir. However, infectivity of mutant viruses is generally compromised. Governments spend millions of dollars on influenza vaccination campaigns; however, once influenza virus is circulating in the community, vaccination cannot limit the spread of disease. A greater promotion of the use of neuraminidase inhibitors for the treatment and prevention of influenza could have a significant impact on limiting its spread. This could result in saving millions of dollars, not only in direct costs associated with medical and hospital care, but also significant savings in indirect costs associated with the loss of productivity at work, school and home environments. For the benefit of all communities, there needs to be a greater awareness of the symptoms of influenza and the efficacy of neuraminidase inhibitors in disease treatment.     

Racial similarities in response to standardized offer of influenza vaccination

BACKGROUND: Despite known benefits of influenza vaccination and coverage by Medicare Part B, elderly minority patients are less likely to receive influenza vaccination than whites. OBJECTIVES: To test whether a nonphysician-initiated standardized offer of influenza vaccination to all elderly primary care patients would result in similar proportions of African-American and white patients accepting vaccine. DESIGN: In 7 metropolitan Detroit primary care practices during the 2003 influenza vaccination season, medical assistants assessed influenza immunization status of all patients 65 years and older and collected limited demographic data. Eligible patients were offered vaccination. MEASUREMENTS: Proportion of patients accepting influenza vaccination by race and predictors of vaccine acceptance. RESULTS: Four hundred and fifty-four eligible patients with complete racial information were enrolled: 40% African American, 52% white, 8% other race/ethnicity. Similar proportions of African Americans and whites had already received the 2003 vaccine (11.6% and 11.0%, respectively) or stated vaccination as the reason for visit (23.8% and 30.5%, respectively). Among the remainder, there also were similar proportions who accepted vaccination: 68.9% white and 62.1% African-American patients. History of previous vaccination was the only statistically significant predictor of vaccine acceptance (odds ratio [OR] 8.64, 95% confidence interval [CI] 4.17, 17.91, P<.001). After adjusting for history of previous vaccination, age, gender, and education, the odds of vaccine acceptance were no different for whites and African Americans (OR 1.20, 95% CI 0.63, 2.29, P=.57). CONCLUSIONS: Vaccination acceptance differed little between African-American and white elderly patients. Using nonphysician personnel to identify and offer influenza vaccine to eligible patients is easily accomplished in primary care offices and has the potential to eliminate racial disparities in influenza vaccination.     

Antibody responses against influenza A(H1N1)pdm09 virus after sequential vaccination with pandemic and seasonal influenza vaccines in Finnish healthcare professionals

Background Influenza A(H1N1)pdm09 virus has been circulating in human population for three epidemic seasons. During this time, monovalent pandemic and trivalent seasonal influenza vaccination against this virus have been offered to Finnish healthcare professionals. It is, however, unclear how well vaccine‐induced antibodies recognize different strains of influenza A(H1N1)pdm09 circulating in the population and whether the booster vaccination with seasonal influenza vaccine would broaden the antibody cross‐reactivity. Objectives Influenza vaccine‐induced humoral immunity against several isolates of influenza A(H1N1)pdm09 virus was analyzed in healthcare professionals. Age‐dependent responses were also analyzed. Methods Influenza viruses were selected to represent viruses that circulated in Finland during two consecutive influenza epidemic seasons 2009–2010 and 2010–2011. Serum samples from vaccinated volunteers, age 20–64 years, were collected before and after vaccination with AS03‐adjuvanted pandemic and non‐adjuvanted trivalent seasonal influenza vaccine that was given 1 year later. Results Single dose of pandemic vaccine induced a good albeit variable antibody response. On day 21 after vaccination, depending on the virus strain, 14–75% of vaccinated had reached antibody titers (≥1:40) considered seroprotective. The booster vaccination 1 year later with a seasonal vaccine elevated the seroprotection rate to 57–98%. After primary immunization, younger individuals (20–48 years) had significantly higher antibody titers against all tested viruses than older persons (49–64 years) but this difference disappeared after the seasonal booster vaccination. Conclusions Even a few amino acid changes in influenza A HA may compromise the vaccine‐induced antibody recognition. Older adults (49 years and older) may benefit more from repeated influenza vaccinations.     

Influenza: the virus and prophylaxis with inactivated influenza vaccine in ��at risk�� groups, including COPD patients

Influenza is a major respiratory pathogen, which exerts a huge human and economic toll on society. Influenza is a vaccine preventable disease, however, the vaccine strains must be annually updated due to the continuous antigenic changes in the virus. Inactivated influenza vaccines have been used for over 50 years and have an excellent safety record. Annual vaccination is therefore recommended for all individuals with serious medical conditions, like COPD, and protects the vaccinee against influenza illness and also against hospitalization and death. In COPD patients, influenza infection can lead to exacerbations resulting in reduced quality of life, hospitalization and death in the most severe cases. Although there is only limited literature on the use of influenza vaccination solely in COPD patients, there is clearly enough evidence to recommend annual vaccination in this group. This review will focus on influenza virus and prophylaxis with inactivated influenza vaccines in COPD patients and other “at risk” groups to reduce morbidity, save lives, and reduce health care costs.     

Patient acceptance of influenza vaccination

PURPOSE: To determine whether patients' demographic, medical, and personal characteristics, including attitudes and beliefs about vaccination, health, and medical providers, are associated with acceptance of influenza vaccine. PATIENTS AND METHODS: Nine hundred sixty-five patients attending a university hospital-based general medicine clinic during the fall influenza vaccination period, including 624 patients for whom influenza vaccine was indicated, were observed in a prospective cohort study. In addition, 58 patients who refused influenza vaccine and an equal number who accepted it were interviewed over the telephone to examine their beliefs and behaviors in greater detail. RESULTS: Seventy-five percent of patients for whom influenza vaccine was indicated received it. Prospectively assessed patient characteristics that were significantly associated with nonvaccination included not believing vaccine prevents "flu" (relative risk [RR] 5.3), never received pneumococcal vaccine (RR 3.5), not vaccinated against influenza the previous year (RR 3.5), never vaccinated against influenza (RR 2.3), and felt sick after previous influenza vaccination (RR 2.3). Demographic characteristics and medical diagnoses were not significantly related to vaccination. Almost one half of 58 interviewed subjects who refused influenza vaccine cited fear of a reaction. Among retrospectively determined attitudes and beliefs significantly associated with refusal of influenza vaccine were not believing the vaccine works well (odds ratio [OR] 11.6), concern about a reaction (OR 9.3), and perception that the medical provider had not recommended it (OR 5.8). CONCLUSION: Demographic characteristics of patients and their medical diagnoses were not associated with acceptance of influenza vaccination. Among patients who were not vaccinated, doubts about the efficacy of influenza vaccine and fear of its side effects were common, and their perceptions of the medical provider's recommendation of vaccine appeared to be an important factor in the decision whether to accept it.     

Immunogenicity of influenza A(H1N1)pdm09 vaccine and the associated factors on lowered immune response in patients with hepatitis C

Background Patients with underlying disease represent a high‐risk group for influenza‐associated complications and hospitalization. However, few studies investigated the immunogenicity of influenza vaccine in patients with liver disease. Objective To examine immunogenicity of influenza A(H1N1)pdm09 vaccine in patients with liver disease and to explore the associated factors on lowered immune response. Patients/Methods A single subcutaneous dose of monovalent inactivated unadjuvanted split‐virus influenza A(H1N1)pdm09 vaccination was performed in 80 patients with chronic hepatitis C virus infection at Osaka City University Hospital in Japan. To measure the hemagglutination inhibition antibody titer, serum samples were collected before and 3 weeks after vaccination. Results No serious adverse events were observed. After vaccination, antibody titers ≥1:40 were observed in 56 patients (71%). The corresponding seroconversion proportion was 72%, and the mean fold rise was 10·3. Immune responses were robust regardless of severity of liver disease or existence of probable cirrhosis. However, patients with older age, lower body mass index, or receiving Stronger Neo‐Minophagen C tended to show lower antibody responses to A(H1N1)pdm09 vaccine. In addition, reduced immune responses were observed in patients who had received the 2009/10 seasonal vaccination prior to A(H1N1)pdm09 vaccination. Conclusions Single dose of A(H1N1)pdm09 vaccine achieved a sufficient level of immunity among patients with chronic hepatitis C. Antibody response may be affected by age, body mass index, Stronger Neo‐Minophagen C administration, and recent seasonal influenza vaccination.     

Serological response to influenza vaccine after hematopoetic stem cell transplantation

Vaccination is the best strategy to prevent influenza infection that is a potential cause of morbidity and mortality in immunosuppressed patients. Here, we evaluated the factors that may affect serological response to influenza vaccine in patients who have undergone hematopoetic stem cell transplantation (HSCT). Sixty-one HSCT recipients were included in the study during the 2007–2008 influenza season. Serum samples prior to vaccination and 6–10 weeks after vaccination were collected. Samples were assayed for antibodies to influenza virus A/H1N1, A/H3N2, and B strains by hemagglutination-inhibition assay. The patients were followed in terms of clinical symptoms up to the next influenza season and for adverse effects within a month after vaccination. Overall, pre-vaccine seroprotection rate against all vaccine antigens (A/H1N1, A/H3N2, and B antigens) was 45.1%, post-vaccine seroprotection rate 91% and seroconversion rate was 28.3%. Seroconversion rates were found to be low against B in patients who were vaccinated in the late influenza season (p = 0.018; respectively). Five patients (10.9%) had no immune response against H1N1. Adverse events were reported in 19.6% (n = 9/46) of the patients. In conclusion, the patients should be vaccinated as early as possible in the influenza season, before they are exposed to the virus.     

Influenza virus-stimulated generation of anti-human immunodeficiency virus (HIV) activity after influenza vaccination in HIV-infected individuals and healthy control subjects

Influenza virus stimulation of leukocytes induces factors that suppress human immunodeficiency virus (HIV). The effect of influenza vaccination on influenza-induced anti-HIV activity was investigated. Influenza vaccine was administered to 25 control subjects and 20 HIV-infected patients. Antiviral activity, cytokine production, and influenza antibodies were assessed before and 2 and 6 weeks after vaccination. Immunization induced a statistically significant increase in antiviral activity in control subjects but not in HIV patients, although the number of patients who generated this activity increased. Pre- and postvaccination levels of anti-HIV activity were significantly lower in HIV patients. Vaccination of control subjects and HIV patients induced increases in production of interleukin-2 and interferon (IFN)-gamma, but not of IFN-alpha. Virus load and CD4 cell counts were not significantly altered. This study demonstrates impairment of antiviral activity in HIV patients, in addition to deficiencies in antibody responses and cytokine production. In summary, influenza vaccination can induce an increase in multiple immunologic components that remained impaired in HIV patients.