Benefits of increasing the dose of influenza vaccine in residents of long-term care facilities: A randomized placebo-controlled trial

Influenza in temperate and tropical Asia: a review of epidemiology and vaccinology

The impact of seasonal influenza has been under-appreciated in Asia and surveillance data lags in most other regions. The variety of influenza circulation patterns in Asia - largely due to the range of climates - has also only recently been recognized and its effect on the burden of disease is not fully understood. Recent reports that clinical protection wanes in the weeks after influenza vaccination emphasize the importance of optimally timing vaccination to local epidemiology. It also raises questions as to whether influenza vaccines should be administered more frequently than annually and what may be the benefits in Asia of access to new vaccines with enhanced immunogenicity and effectiveness. This review will summarize influenza surveillance data from Asian countries over 2011-2018, and consider the implications for vaccination strategies in different parts of Asia.

Serum C-Reactive Protein and Congestive Heart Failure as Significant Predictors of Herpes Zoster Vaccine Response in Elderly Nursing Home Residents

Background

Elderly long-term care residents often exhibit a myriad of risk factors for immune dysfunction, including chronic inflammation and multiple comorbid conditions, which undoubtedly contribute to their enhanced susceptibility to infection. Hence, understanding the factors required for optimal vaccine responsiveness is critical.

Methods

We examined 187 elderly nursing home residents (aged 80-102 years) and 50 community-dwelling seniors (aged 60-75 years) immunized with the live-attenuated varicella-zoster virus (VZV) vaccine. Specifically, we examined whether vaccine responsiveness was associated with serum C-reactive protein (CRP), tumor necrosis factor, interleukin 1β, 6, and 10, leukocyte telomere length, chronic disease status, and frailty.

Results

Elderly participants had significantly higher levels of CRP, tumor necrosis factor, and interleukin 6 and shorter leukocyte telomere length. Vaccine responsiveness was inversely related to the CRP level in elderly participants, but not seniors, and those with congestive heart failure were less likely to achieve a 2-fold response (odds ratio, 0.08). The latter relationship is probably due to immunosenescence, because heart failure was associated with increased senescent CD4+ T cells, and reduced naive and effector and central memory CD8+ T cells.

Conclusions

In summary, these data improve our understanding of vaccine responsiveness for those in long-term care, suggesting that certain risk factors are associated with a greater likelihood of vaccine failure.

Effectiveness of post-exposition prophylaxis with oseltamivir in nursing homes: a randomised controlled trial over four seasons

Background

Oseltamivir has been registered for use as post-exposition prophylaxis (PEP) following exposure to influenza, based on studies among healthy adults. Effectiveness among frail elderly nursing home populations still needs to be properly assessed.

Methods

We conducted a randomised double-blind placebo-controlled trial of PEP with either oseltamivir (75 mg once daily) or placebo among nursing home units where influenza virus was detected; analysis was unblinded. The primary outcome was laboratory-confirmed influenza among residents in units on PEP; the secondary outcome was clinical diagnosis of influenza-like illness (ILI).

Results

42 nursing homes were recruited, in which 17 outbreaks occurred from 2009 through 2013, two caused by influenza virus B, the others caused by influenza virus A(H3N2). Randomisation was successful in 15 outbreaks, with a few chance differences in baseline indicators. Six outbreaks were assigned to oseltamivir and nine to placebo. Influenza virus positive secondary ILI cases were detected in 2/6 and 2/9 units respectively (ns); secondary ILI cases occurred in 2/6 units on oseltamivir, and 5/9 units on placebo (ns). Logistical challenges in ensuring timely administration were considerable.

Conclusion

We did not find statistical evidence that PEP with oseltamivir given to nursing home residents in routine operational settings exposed to influenza reduced the risk of new influenza infections within a unit nor that of developing ILI. Power however was limited due to far fewer outbreaks in nursing homes than expected since the 2009 pandemic. (RCT nr NL92738)

Better immunity in later life: a position paper

Ageing is the greatest challenge that health-care systems will have to deal with this century. This is because a wide spectrum of pathological impairments emerge in the later part of the human life course which sharply increase mortality and reduce quality of life. Dysfunction of the immune system with advancing age is of crucial importance to the development of disability in later life and finally death. Understanding immune ageing, immunosenescence, has long been recognised as an essential prerequisite for the delivery of effective interventions which will improve late life health. Ten years ago, the ImAginE consortium undertook a broad ranging series of projects which added significantly to our understanding of how fundamental ageing mechanisms drove immune decline. In the decade which followed, abundant evidence has accumulated from nonhuman model systems that ageing results from the progressive operation of a relatively few common processes which act across the major organ systems. These advances in fundamental understanding both allow better clarification of the potential cross-system dysregulation that occurs in ageing and open new avenues for intervention. Over the course of a 2-day workshop, the original ImAginE participants have considered these issues and present some suggestions for current priority areas in immunosenescence.

Factors influencing the efficacy of two injections of a pandemic 2009 influenza A (H1N1) nonadjuvanted vaccine in systemic lupus erythematosus

OBJECTIVE

To assess the factors influencing the efficacy of 2 injections of a pandemic 2009 influenza A (H1N1) vaccine in patients with systemic lupus erythematosus (SLE).

METHODS

We conducted a single-center, observational prospective study of 111 patients who were vaccinated with a monovalent, inactivated, nonadjuvanted, split-virus vaccine during December 2009 and January 2010 and received a second dose of vaccine 3 weeks later. The antibody response was evaluated using the hemagglutination inhibition assay according to the guidelines recommended for the pandemic vaccine, consisting of 3 immunogenicity criteria (i.e., a seroprotection rate of 70%, a seroconversion rate of 40%, and a geometric mean ratio [GMR] of 2.5).

RESULTS

The 3 immunogenicity criteria were met on day 42 (seroprotection rate 80.0% [95% confidence interval (95% CI) 72.5-87.5%], seroconversion rate 71.8% [95% CI 63.4-80.2%], and GMR 10.3 [95% CI 2.9-14.2]), while only 2 criteria were met on day 21 (seroprotection rate 66.7% [95% CI 57.9-75.4%], seroconversion rate 60.4% [95% CI 51.3-69.5%], and GMR 8.5 [95% CI 3.2-12.0]). The vaccine was well tolerated. Disease activity, assessed by the Safety of Estrogens in Lupus Erythematosus National Assessment version of the SLE Disease Activity Index, the British Isles Lupus Assessment Group score, and the Systemic Lupus Activity Questionnaire, did not increase. In the multivariate analysis, vaccination failure was significantly associated with immunosuppressive treatment or a lymphocyte count of ≤ 1.0 × 10⁹/liter. The second injection significantly increased the immunogenicity in these subgroups, but not high enough to fulfill the seroprotection criterion in patients receiving immunosuppressive treatment.

CONCLUSION

Our findings indicate that the efficacy of the vaccine was impaired in patients who were receiving immunosuppressive drugs or who had lymphopenia. A second injection increased vaccine immunogenicity without reaching all efficacy criteria for a pandemic vaccine in patients receiving an immunosuppressive agent. These results open possibilities for improving anti-influenza vaccination in SLE.

Vaccines for the elderly

Vaccination is the most efficient strategy to prevent infectious disease. The increased vulnerability to infection of the elderly makes them a particularly important target population for vaccination. However, most vaccines are less immunogenic and efficient in the elderly because of age-related changes in the immune system. Vaccination against influenza, Streptococcus pneumoniae and varicella zoster virus is recommended for the elderly in many countries. Various strategies such as the use of adjuvants and novel administration routes are pursued to improve influenza vaccination for the elderly and recent developments in the field of pneumococcal vaccination led to the licensure of protein-conjugated polysaccharide vaccines containing up to 13 serotypes. As antibody titres are generally lower in the elderly and-particularly for inactivated vaccines-decline fast in the elderly, regular booster immunizations, for example against tetanus, diphtheria and, in endemic areas, tick-borne encephalitis, are essential during adulthood to ensure protection of the elderly. With increasing health and travel opportunities in old age the importance of travel vaccines for persons over the age of 60 is growing. However, little is known about immunogenicity and efficacy of travel vaccines in this age group. Despite major advances in the field of vaccinology over the last decades, there are still possibilities for improvement concerning vaccines for the elderly. Novel approaches, such as viral vectors for antigen delivery, DNA-based vaccines and innovative adjuvants, particularly toll-like receptor agonists, will help to achieve optimal protection against infectious diseases in old age.

Absence of influenza A(H1N1) during seasonal and pandemic seasons in a sentinel nursing home surveillance network in the Netherlands

OBJECTIVES

To describe the epidemiological, virological, and institutional characteristics of influenza-like illness (ILI) in nursing homes (NHs).

DESIGN

Continuous clinical surveillance of ILI and virological surveillance of ILI and other acute respiratory infections (ARIs) during four influenza seasons.

SETTING

National sentinel NH surveillance network.

PARTICIPANTS

National sentinel residents.

MEASUREMENTS

Weekly registration of ILI cases (influenza seasons 2008/09-2009/10), influenza virus detection (influenza seasons 2006/07-2009/10), and collection of institutional characteristics of NHs at start of participation.

RESULTS

During the 2008/09 influenza season, ILI incidence started to rise in Week 49 of 2008, peaked in Week 3 of 2009 (158 cases per 10,000 resident weeks), and flattened out by Week 16 of 2009 (mean ILI incidence during epidemic: 73 cases per 10,000 resident weeks). During the 2009/10 influenza pandemic, there was no epidemic peak. Influenza virus type and subtype varied throughout virological surveillance but was limited to influenza A(H3N2) and B viruses. Higher staff vaccination coverage (>15%) was associated with lower ILI-incidence in the 2008/09 influenza season in a univariate negative binomial regression analysis (incidence rate ratio = 0.3, 95% confidence interval = 0.1-0.8)).

CONCLUSION

Neither seasonal nor pandemic influenza A(H1N1) viruses were detected in the network, despite widespread community transmission of seasonal and influenza A(H1N1) virus. ILI incidence trends corresponded to virological trends. Sentinel surveillance of ILI combining clinical and virological data in NHs increases understanding of transmission risks in this specific vulnerable population.

Cytomegalovirus infection and responsiveness to influenza vaccination in elderly residents of long-term care facilities

Ample evidence suggests that infection with cytomegalovirus (CMV) leads to accelerated aging of the immune system and may contribute to poor responsiveness to influenza vaccination in older persons. The objective of this study was to investigate whether CMV infection, acquired earlier in life, affects the response to influenza vaccination in a randomized controlled trial among older persons in long-term care facilities. During the 1997-1998 influenza season, 731 residents (median age 83 [interquartile range 78-88], 75.4% female) in 14 long-term care facilities in the Netherlands were randomly assigned to receive 15 or 30 μg of inactivated influenza vaccine, followed by a 15 μg booster vaccine or a placebo vaccine at day 84. Blood samples were collected at day 0, day 25, day 84 and day 109. Seroresponses to influenza vaccination were measured by hemagglutination-inhibition tests to the A/H3N2 strain at all time points. Subsequently, baseline levels of IgG anti-CMV antibodies were measured using an automated chemiluminescent microparticle immunoassay. Participants with CMV antibody level≥6 AU/mL were considered to harbor CMV infection. At baseline, no differences in pre-vaccination geometric mean antibody titers (GMT) were observed between participants with (n=571, 78.1%) or without CMV infection (n=160, 21.9%). During follow-up, participants with and without CMV infection had similar responses to influenza vaccination as measured with changes in GMT (linear mixed model, adjusted for gender, age, pre-vaccination GMT and vaccination strategy, p=0.46). Analogously, no association was found between CMV infection and a more than 4-fold increase in antibody titer (Generalized Estimating Equations, adjusted OR 1.14 [95%CI 0.80;1.64]) or an antibody titer≥40 (adjusted OR 1.24 [95%CI 0.86;1.80]). In conclusion, CMV infection did not explain poor responsiveness to influenza vaccination in residents of long-term care facilities.