Universal vaccination of healthy children against influenza: a role for the cold-adapted intranasal influenza vaccine

Outbreak of influenza A in a boarding school in South Africa, 2016

Introduction

We investigated an outbreak of influenza-like illness (ILI) at a boarding school in Eastern Cape Province, South Africa. We aimed to confirm the etiological agent, estimate attack rates and identify risk factors for illness.

Methods

We conducted a retrospective cohort study including senior school boarders (n=308). Students with ILI (cough and fever) were identified through school medical records. We also conducted a questionnaire-based cross-sectional study among senior students including boarders (n=107) and day students (n=45). We collected respiratory specimens for respiratory pathogen testing by real-time polymerase chain reaction from a subset of symptomatic students. We calculated attack rates of medically attended ILI (medILI) and identified factors associated with medILI using logistic regression. We calculated seasonal influenza vaccine effectiveness (VE) against medILI.

Results

Influenza A (H3N2) virus was detected in 61% (23/38) of specimens. Attack rate for medILI was 13% among boarders (39/308) in the cohort study and 20% in both day students (9/45) and boarders (21/107) in the cross-sectional study. Playing squash was associated with medILI (aOR 5.35, 95% confidence interval [95% CI]: 1.68-17.07). Of the boarders, 19% (57/308) were vaccinated before the outbreak. The adjusted VE against medILI was 18% (aOR 0.82, 95% CI 0.38-1.78). The outbreak led to cancellation of several events and the need for academic remedial sessions.

Conclusion

We confirmed an influenza A (H3N2) virus outbreak with a high attack rate. The outbreak affected academic and sports activities. Participation in sports and social gatherings while experiencing ILI should be discouraged to reduce viral transmission and impact on school activities.

Efficacy of LAIV-T on absentee rates in a school-based health center sample

PURPOSE

To determine the effectiveness of the intranasal LAIV-T in decreasing school absenteeism in a school-based vaccination initiative and to compare the acceptability of LAIV-T versus TIV among adolescents.

METHODS

This study was conducted within a single, urban community high school in the Fall of 2006. Participation was offered to all students in grades 6 to 10, aged 11 to 17 years. In December, school health center staff administered influenza vaccines to the students whose parents had returned written consent. Students received LAIV-T (n = 86), unless they were medically ineligible or objected; in those cases the injectable inactivated trivalent influenza vaccine (TIV) (n = 41) was offered. Students that did not receive either vaccination served as a control group (n = 234). Nonsuspension absences between January and June of 2007 were tracked for all three groups.

RESULTS

Students who received the LAIV-T had significantly less nonsuspension absences (mean absences = 5.53, SD = 5.00) compared to both the TIV (mean absences = 9.45, SD = 9.07) and control groups (mean absences = 7.97, SD =7.59).

CONCLUSIONS

LAIV-T was associated with a reduction in nonsuspension absences and was well accepted by students. Administration of LAIV-T may be a convenient and effective method to mass-immunize students in a school setting and help establish herd immunity within the community.

Adverse events associated with intranasal influenza vaccine in the United States

METHODS

The goal of this review was to analyze the post-vaccination adverse effects associated with Live Attenuated Influenza Vaccine (LAIV) compared to those of the Injectable Trivalent Inactivated Vaccine (TIV) in patients with egg allergy and asthma. PubMed, Ovid, and Google searches were conducted. Searched articles relating to allergic reactions, asthma or food allergy, and LAIV were reviewed.

RESULTS

Similar or superior efficacy of LAIV compared to TIV was reported by various studies. Respiratory symptoms were the most common adverse events following both vaccinations. Although no evidence was found of a direct causal relationship between intranasal influenza vaccine and anaphylaxis due to egg allergy, a number of cases of anaphylaxis were reported. To date, there are no studies directly comparing the frequency of anaphylactic reactions between the two vaccines.

CONCLUSIONS

The safety of LAIV in individuals with unstable asthma and egg allergy has not been established and it should be avoided in these populations. For patients with unstable asthma, TIV should remain the therapy of choice.

The impact of influenza on working days lost: a review of the literature

Seasonal influenza is a prevalent and highly contagious acute respiratory disease that, year on year, results in increased morbidity and mortality on a global scale. Because of the widespread and debilitating nature of the disease, annual influenza epidemics result in substantial workplace absenteeism, and the associated cost of lost productivity is a significant component of the substantial financial burden of the disease to society. The objective of this review was to identify studies that had attempted to quantify the impact of influenza upon otherwise healthy adults in terms of working days lost associated with an episode of influenza.Studies were included if they reported estimates of working days lost due to clinical, physician and/or self-diagnosis in adult patients or their dependants, or where this figure could be estimated from the data. Searches were conducted in MEDLINE, EMBASE, BIOSIS and the Cochrane Collaboration for articles published since 1995 in English, French or German. Of the 289 papers identified in the search, 28 (9.7%) met the inclusion criteria. The studies, involving study sites in North America, Western Europe, Asia and Australia, were categorized into three groups: (i) those reporting influenza diagnoses confirmed by laboratory testing, i.e. studies where influenza was the unambiguous cause of the working days lost (n = 7 studies reported in ten publications); (ii) those where influenza was confirmed by a physician without an accompanying laboratory test (n = 4 studies); and (iii) those where influenza was self-reported by study participants (n = 14 studies). Qualitative reporting of results was performed because of the large degree of heterogeneity observed between studies, potentially complicating the interpretation of any meta-analysis.The results from studies involving a laboratory-confirmed influenza diagnosis suggested that the mean number of working days lost ranged between 1.5 and 4.9 days per episode. Those papers that detailed working days lost per episode following physician diagnosis of influenza reported a range of 3.7-5.9 days per episode. Finally, estimates from papers reporting working days lost per episode of self-reported influenza ranged from <1 day to 4.3 days per episode.Influenza imposes a significant burden on society, and this review highlights the significant economic impact it causes, i.e. the loss of productivity caused by both absenteeism and by staff functioning at reduced capacity even after they have returned to work. A number of prophylaxis and treatment options exist for influenza and should be given serious consideration in an attempt to reduce the economic burden on society.

Role of influenza vaccine for healthy children in the US

Influenza infection is associated with significant morbidity and mortality in adults, but the highest attack rates for influenza regularly occur in children, particularly those in preschool and elementary school. The consequences of influenza in this younger population - increased rate of hospitalization in those younger than 2 years of age and serious associated morbidity - have been underestimated. Children are also the critical link for spreading influenza in the community. Recent data suggest that mass influenza vaccination of healthy children would not only protect recipients, but also may reduce the burden of influenza throughout the community. During the past 3 decades, efforts to control influenza have focused on the use of an injectable trivalent inactivated vaccine (TIV) in high-risk persons. The vaccine is 'safe' and effective, but its acceptance and uptake by patients and healthcare providers have been modest at best. A new intranasal, live-attenuated, trivalent cold-adapted influenza virus vaccine (CAIV-T) [FluMist] is 'safe', well tolerated, immunogenic, and efficacious in preventing influenza illness in healthy children. Compared with TIV, CAIV-T is easier to administer and should be more readily acceptable, particularly for mass immunization campaigns. CAIV-T also induces a broader immune response and has demonstrated protection against at least three different variant influenza strains. This vaccine is particularly well suited for routine immunization of children and thus offers the potential for greatly improved control of influenza. However, the acquisition cost per single dose of FluMist for the 2003-4 season ( approximate, equals 46 US dollars) significantly hampered its uptake both by practitioners and by managed care organizations, even despite a later approximate, equals 25 US dollars rebate offer. For the 2004-5 season, CAIV-T is likely to be only modestly more expensive (average wholesale price: 16.50 US dollars for non-returnable doses, 23 US dollars for returnable doses) than TIV. The practitioner must consider the benefits of FluMist compared with its likely higher vaccine cost and the issues of reimbursement among multiple insurers.

Trivalent Intranasal Influenza Vaccine, Live

OBJECTIVE

To review human data on the efficacy, safety, and clinical use of trivalent intranasal influenza vaccine, live (TIIVL).

DATA SOURCES

A MEDLINE search (1966–3rd week of January 2004) using the terms influenza vaccine, intranasal administration, and FluMist was conducted. References from pertinent articles were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

Studies conducted in humans and published in English were selected. Double-blind, controlled trials evaluating the efficacy and safety of TIIVL were evaluated.

DATA SYNTHESIS

Administration of TIIVL results in mucosal and humoral immunity to influenza. Results of clinical trials in children and adults have demonstrated that TIIVL reduces the incidence of influenza. In children, TIIVL was also associated with a decrease in febrile illness and febrile otitis media. In adults, reductions in workday absences and medical visits due to febrile upper respiratory tract illness were also documented. TIIVL is well tolerated, with rhinorrhea or nasal congestion and sore throat occurring more frequently than with placebo.

CONCLUSIONS

TIIVL is an alternative to intramuscular inactivated influenza vaccine in healthy individuals between 5 and 49 years of age. However, the vaccine is contraindicated in the majority of patient populations for whom annual influenza vaccination is recommended. THIS ARTICLE IS APPROVED FOR CONTINUING EDUCATION CREDIT ACPE UNIVERSAL PROGRAM NUMBER: 407-000-04-037-H01

Every nose counts: a new influenza vaccine for all healthy schoolchildren?

Influenza is a vaccine-preventable disease. However, influenza virus spreads among children in schools and daycare centers, then to families and communities, causing uncontrolled epidemics every winter. The United States Food and Drug Administration evaluated and approved an investigational live-attenuated, cold-adapted, trivalent influenza vaccine for licensure, for prevention of influenza in healthy children and healthy adults, 5 through 49 years of age. Could protection of healthy schoolchildren against influenza limit its spread and benefit society?

Effectiveness of influenza vaccination of children with recurrent respiratory tract infections in reducing respiratory-related morbidity within the households

To evaluate the effectiveness of influenza vaccination in reducing respiratory-related morbidity among children with recurrent respiratory tract infections (RRTIs) and their household contacts, 127 children aged 6 months-9 years (78 males; median age, 3.7 years) with a history of RRTIs (>/=6 episodes per year if aged >/=3 years; >/=8 episodes per year if aged <3 years) were randomized to receive the intranasal virosomal influenza vaccine (n=64 with 176 household contacts) or a control placebo (n=63 with 173 household contacts). During influenza season, the vaccinated children had fewer respiratory infections, febrile respiratory illnesses, prescribed antibiotics and antipyretics, and missed school days than the controls, and similar benefits and a reduction in the loss of parental work were observed among their household contacts. This study shows that the benefits of influenza vaccination extend to children with RRTIs and their family members and encourages to recommend its use in such children.