Vaccines for preventing influenza in healthy adults (original) (raw)
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Evaluation of a single dose of half strength inactivated influenza vaccine in healthy adults
Vaccine, 2002
Because of delays in the manufacturing of the 2000-2001, trivalent inactivated influenza vaccine in the US, there were concerns that there might be shortages of vaccine supply in the US. Therefore, we conducted a prospective, randomized, open-label, multicenter trial at six academic medical centers in the US, to evaluate the immunogenicity of a half dose of inactivated vaccine in healthy adults. Healthy adults between the ages of 18 and 49 were randomized to receive either a full 0.5ml (15.5 microg of each HA antigen) dose or a 0.25ml (7.75 microg of each HA antigen) dose of the 2000-2001 trivalent inactivated influenza vaccine by intramuscular injection. Sera were obtained for assessment of hemagglutination-inhibiting antibody to each of the three strains contained in the vaccine before and 21 days after vaccination. The proportions of individuals achieving a post-vaccination titer of > or =1:40, the geometric mean titers (GMTs) of post-vaccination antibody, and the proportions ...
The Lancet Infectious Diseases, 2020
Background Influenza is an important public health problem and existing vaccines are not completely protective. New vaccines that protect by alternative mechanisms are needed to improve efficacy of influenza vaccines. In 2015, we did a phase 1 trial of an oral influenza vaccine, VXA-A1.1. A favourable safety profile and robust immunogenicity results in that trial supported progression of the vaccine to the current phase 2 trial. The aim of this study was to evaluate efficacy of the vaccine in a human influenza challenge model. Methods We did a single-site, placebo-controlled and active-controlled, phase 2 study at WCCT Global, Costa Mesa, CA, USA. Eligible individuals had an initial A/California/H1N1 haemagglutination inhibition titre of less than 20 and were aged 18-49 years and in good health. Individuals were randomly assigned (2:2:1) to receive a single immunisation of either 10¹¹ infectious units of VXA-A1.1 (a monovalent tablet vaccine) orally, a full human dose of quadrivalent inactivated influenza vaccine (IIV) via intramuscular injection, or matched placebo. Randomisation was done by computergenerated assignments with block size of five. An unmasked pharmacist provided the appropriate vaccines and placebos to the administrating nurse. Individuals receiving the treatments, investigators, and staff were all masked to group assignments. 90 days after immunisation, individuals without clinically significant symptoms or signs of influenza, an oral temperature of higher than 37•9°C, a positive result for respiratory viral shedding on a Biofire test, and any investigator-assessed contraindications were challenged intranasally with 0•5 mL wild-type A/CA/like(H1N1)pdm09 influenza virus. The primary outcomes were safety, which was assessed in all immunised participants through 365 days, and influenza-positive illness after viral challenge, which was assessed in individuals that received the viral challenge and the required number of assessments post viral challenge. This trial is registered with ClinicalTrials.gov, number NCT02918006.
Vaccine, 2011
Purpose: To systematically review the evidence regarding the efficacy, effectiveness and risks of the use of inactivated influenza vaccines in children, healthy adults, elderly individuals and individuals with comorbidities such as diabetes, chronic lung disease, cardiovascular disease, kidney or liver disease and immune suppression. Methods: The Cochrane database of systematic reviews was searched for relevant reviews and supplemented with searches of the Cochrane Central Register of Controlled Trials database and Medline. Two reviewers independently assessed review and trial quality and extracted data. Results and conclusions: The inactivated influenza vaccine has been proven effective in preventing laboratory-confirmed influenza among healthy adults (16-65 years) and children (≥6 years) (GRADE A evidence). However, there is strikingly limited good-quality evidence (all GRADE B, C or not existing) of the effectiveness of influenza vaccination on complications such as pneumonia, hospitalisation and influenza-specific and overall mortality. Inconsistent results are found in studies among children younger than 6 years, individuals with COPD, institutionalised elderly (65 years or older), elderly with co-morbidities and healthcare workers in elderly homes, which can only be explained by bias of unknown origin. The vaccination of pregnant women might be beneficial for their newborns, and vaccination of children might be protective in non-recipients of the vaccine of all ages living in the same community (one RCT, Grade B evidence).
Vaccine, 2011
Several inactivated influenza vaccine formulations for systemic administration in man are currently available for annual (seasonal) immunization: split virus and subunit (either plain-aqueous, or virosomal, or adjuvanted by MF59). From a literature search covering the period 1978-2009, 33 articles could be identified, which described randomized clinical trials comparing at least two of the four vaccine formulations with respect to serum hemagglutination inhibition (HI) antibody response, local and systemic vaccine reactions and serious adverse events after vaccination, and employing seasonal vaccine components and doses. In total, 9121 vaccinees of all ages, either healthy or with underlying diseases, were involved. Most vaccinees were primed or had been vaccinated in previous years.
Vaccines for preventing influenza in healthy children
Evidence-based Child Health: A Cochrane Review Journal, 2006
BackgroundIn children and adults the consequences of influenza are mainly absences from school and work, however the risk of complications is greatest in children and people over 65 years old.In children and adults the consequences of influenza are mainly absences from school and work, however the risk of complications is greatest in children and people over 65 years old.ObjectivesTo appraise all comparative studies evaluating the effects of influenza vaccines in healthy children; assess vaccine efficacy (prevention of confirmed influenza) and effectiveness (prevention of influenza-like illness) and document adverse events associated with receiving influenza vaccines.To appraise all comparative studies evaluating the effects of influenza vaccines in healthy children; assess vaccine efficacy (prevention of confirmed influenza) and effectiveness (prevention of influenza-like illness) and document adverse events associated with receiving influenza vaccines.Search strategyWe searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2005); OLD MEDLINE (1966 to 1969); MEDLINE (1969 to December 2004); EMBASE (1974 to December 2004); Biological Abstracts (1969 to December 2004); and Science Citation Index (1974 to December 2004). We wrote to vaccine manufacturers and a number of corresponding authors of studies in the review.We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2005); OLD MEDLINE (1966 to 1969); MEDLINE (1969 to December 2004); EMBASE (1974 to December 2004); Biological Abstracts (1969 to December 2004); and Science Citation Index (1974 to December 2004). We wrote to vaccine manufacturers and a number of corresponding authors of studies in the review.Selection criteriaAny randomised controlled trials (RCTs), cohort and case-control studies of any influenza vaccine in healthy children under 16 years old.Any randomised controlled trials (RCTs), cohort and case-control studies of any influenza vaccine in healthy children under 16 years old.Data collection and analysisTwo authors independently assessed trial quality and extracted data.Two authors independently assessed trial quality and extracted data.Main resultsFifty-one studies involving 263,987 children were included. Seventeen papers were translated from Russian. Fourteen RCTs and 11 cohort studies were included in the analysis of vaccine efficacy and effectiveness. From RCTs, live vaccines showed an efficacy of 79% (95% confidence interval (CI) 48% to 92%) and an effectiveness of 33% (95% CI 28% to 38%) in children older than two years compared with placebo or no intervention. Inactivated vaccines had a lower efficacy of 59% (95% CI 41% to 71%) than live vaccines but similar effectiveness: 36% (95% CI 24% to 46%). In children under two, the efficacy of inactivated vaccine was similar to placebo. Thirty-four reports containing safety outcomes were included, 22 including live vaccines, 8 inactivated vaccines and 4 both types. The most commonly presented short-term outcomes were temperature and local reactions. The variability in design of studies and presentation of data was such that meta-analysis of safety outcome data was not feasible.Fifty-one studies involving 263,987 children were included. Seventeen papers were translated from Russian. Fourteen RCTs and 11 cohort studies were included in the analysis of vaccine efficacy and effectiveness. From RCTs, live vaccines showed an efficacy of 79% (95% confidence interval (CI) 48% to 92%) and an effectiveness of 33% (95% CI 28% to 38%) in children older than two years compared with placebo or no intervention. Inactivated vaccines had a lower efficacy of 59% (95% CI 41% to 71%) than live vaccines but similar effectiveness: 36% (95% CI 24% to 46%). In children under two, the efficacy of inactivated vaccine was similar to placebo. Thirty-four reports containing safety outcomes were included, 22 including live vaccines, 8 inactivated vaccines and 4 both types. The most commonly presented short-term outcomes were temperature and local reactions. The variability in design of studies and presentation of data was such that meta-analysis of safety outcome data was not feasible.Authors' conclusionsInfluenza vaccines are efficacious in children older than two years but little evidence is available for children under two. There was a marked difference between vaccine efficacy and effectiveness. That no safety comparisons could be carried out emphasizes the need for standardisation of methods and presentation of vaccine safety data in future studies. It was surprising to find only one study of inactivated vaccine in children under two years, given recent recommendations to vaccinate healthy children from six months old in the USA and Canada. If immunisation in children is to be recommended as public-health policy, large-scale studies assessing important outcomes and directly comparing vaccine types are urgently required.Influenza vaccines are efficacious in children older than two years but little evidence is available for children under two. There was a marked difference between vaccine efficacy and effectiveness. That no safety comparisons could be carried out emphasizes the need for standardisation of methods and presentation of vaccine safety data in future studies. It was surprising to find only one study of inactivated vaccine in children under two years, given recent recommendations to vaccinate healthy children from six months old in the USA and Canada. If immunisation in children is to be recommended as public-health policy, large-scale studies assessing important outcomes and directly comparing vaccine types are urgently required.Plain language summaryThis review found nasal spray vaccines are better than injected vaccines at preventing influenza in children; neither were particularly good at preventing influenza-like illnessThis review assessed how good influenza vaccines were in preventing 'flu' in children who are normally healthy. Nasal spray vaccines made from weakened influenza viruses, were better at preventing illness caused by the influenza virus than injected vaccines made from killed virus. Neither type was particularly good at preventing 'flu-like illness' caused by other types of viruses. A large amount of information was collected comparing reactions in children who had received vaccines with those who had not. However, the vaccine types could not be compared because of the different ways the data were collected and presented in the studies. It was not possible to analyse the safety of vaccines from the studies due to the lack of standardisation in the information given. Very little information was found on the safety on inactivated vaccines, the most commonly used, in young children. Copyright © 2006 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.This review found nasal spray vaccines are better than injected vaccines at preventing influenza in children; neither were particularly good at preventing influenza-like illnessThis review assessed how good influenza vaccines were in preventing 'flu' in children who are normally healthy. Nasal spray vaccines made from weakened influenza viruses, were better at preventing illness caused by the influenza virus than injected vaccines made from killed virus. Neither type was particularly good at preventing 'flu-like illness' caused by other types of viruses. A large amount of information was collected comparing reactions in children who had received vaccines with those who had not. However, the vaccine types could not be compared because of the different ways the data were collected and presented in the studies. It was not possible to analyse the safety of vaccines from the studies due to the lack of standardisation in the information given. Very little information was found on the safety on inactivated vaccines, the most commonly used, in young children. Copyright © 2006 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Prevention and early treatment of influenza in healthy adults
Vaccine, 2000
We present three systematic reviews carried out within the Cochrane Collaboration, focusing on a dierent in¯uenza intervention in healthy adults: Vaccines; Ion Channel Inhibitor antivirals and Neuraminidase Inhibitor (NIs) antivirals. The objectives were to identify, retrieve and assess all studies evaluating the eects of these interventions in prophylaxis and early treatments of in¯uenza and the frequency of adverse events. Additionally we present the results of the economic evaluation of eective alternatives in order to de®ne the most cost-eective intervention. The economic evaluation is set in the context of the British Army.
2004
This article compares influenza vaccination rates in 1996/97 and 2000/01 and describes the characteristics of adults who were vaccinated.
Vaccine, 2012
Introduction: We estimated influenza vaccine effectiveness (IVE) to prevent laboratory-confirmed influenza-related hospitalizations in patients 18 years old or older during the 2010-2011 influenza season. Methods: We conducted a prospective case-control study in five hospitals, in Valencia, Spain. Study subjects were consecutive emergency hospitalizations for predefined conditions associated with an influenza-like illness episode <8 days before admission. Patients were considered immunized if vaccinated ≥14 days before influenza-like illness onset. Cases were those with a real time reverse transcriptase polymerase chain reaction (RT-PCR) positive for influenza and controls were RT-PCR positive for other respiratory viruses. Adjusted IVE was estimated as 100 × (1 − adjusted odds ratio). To account for indication bias we computed adjusted IVE for respiratory syncytial virus related hospitalizations. Results: Of 826 eligible hospitalized patients, 102 (12%) were influenza positive and considered cases, and 116 (14%) were positive for other respiratory viruses and considered controls. Adjusted IVE was 54% (95% confidence interval, 11-76%). By subgroup, adjusted IVE was 53% (4-77%) for those with high-risk conditions, 59% (16-79%) for those ≥60 years of age, and, 54% (4-79%) for those ≥60 years of age with high-risk conditions. No influenza vaccine effect was observed against respiratory syncytial virus related hospitalization. Conclusion: Influenza vaccination was associated with a significant reduction on the risk of confirmed influenza hospitalization, irrespective of age and high-risk conditions.
Influenza Vaccination Strategies: Comparing Inactivated and Live Attenuated Influenza Vaccines
Vaccines, 2015
Influenza is a major respiratory pathogen causing annual outbreaks and occasional pandemics. Influenza vaccination is the major method of prophylaxis. Currently annual influenza vaccination is recommended for groups at high risk of complications from influenza infection such as pregnant women, young children, people with underlying disease and the elderly, along with occupational groups such a healthcare workers and farm workers. There are two main types of vaccines available: the parenteral inactivated influenza vaccine and the intranasal live attenuated influenza vaccine. The inactivated vaccines are licensed from 6 months of age and have been used for more than 50 years with a good safety profile. Inactivated vaccines are standardized according to the presence of the viral major surface glycoprotein hemagglutinin and protection is mediated by the induction of vaccine strain specific antibody responses. In contrast, the live attenuated vaccines are licensed in Europe for children from 2-17 years of age and provide a multifaceted immune response with local and systemic antibody and T cell responses but with no clear correlate of protection. Here we discuss the immunological immune responses elicited by the two vaccines and discuss future work to better define correlates of protection. OPEN ACCESS Vaccines 2015, 3 374