A trivalent, inactivated influenza vaccine (Vaxigrip®): summary of almost 50 years of experience and more than 1.8 billion doses distributed in over 120 countries

A randomized, double-blind, non-inferiority trial comparing the immunogenicity and safety of two seasonal inactivated influenza vaccines in adults

BACKGROUND

To enhance the production and availability of influenza vaccines in different regions of the world is paramount to mitigate the global burden of this disease. Instituto Butantan developed and manufactured an embryonated egg-based inactivated split-virion trivalent seasonal influenza vaccine as part of a technology transfer partnership with Sanofi Pasteur.

METHODS

This is a phase IV, randomized, double-blind, active-controlled, multicenter clinical trial including adults 18-60 and > 60 years recruited during the 2019 southern hemisphere influenza season. Subjects were randomized 1:1 to receive either the Sanofi Pasteur Trivalent Seasonal Influenza Vaccine (SP-TIV) or Instituto Butantan Trivalent Seasonal Influenza Vaccine (IB-TIV). Hemagglutinin inhibition antibody titers were assessed pre-vaccination and 21 days post-vaccination.

RESULTS

624 participants were randomized and vaccinated. In both intention-to-treat and per-protocol analysis, non-inferiority of the SP-TIV versus IB-TIV was demonstrated for the three influenza strains. In the per-protocol analysis, the SP-GMT/IB-GMT ratios for H1N1, H3N2, and B were 0.9 (95%CI, 0.7-1.1), 1.2 (95%CI, 1.0-1.4), and 1.1 (95%CI, 0.9-1.3), respectively. Across vaccination groups, the most common adverse reactions (AR) were limited to the injection-site, including pain and tenderness. The majority of the ARs were graded 1 and/or 2 and lasted less than one day. No serious adverse reaction was observed.

CONCLUSION

This study demonstrated the non-inferiority of the immunogenicity of a single-dose of Instituto Butantan versus a single dose of the Sanofi Pasteur Seasonal Trivalent Influenza Vaccine in adults. Both vaccines were well tolerated and presented similar safety profiles.

Safety and Impact on Training of the Influenza Vaccines in Elite Athletes Participating in the Rio 2016 Olympics

OBJECTIVE

The aim of the study was to evaluate the safety and tolerance of influenza vaccines for the northern and southern hemispheres in Polish elite athletes participating in the Rio 2016 Olympics.

DESIGN

Prospective, observational, cohort study.

SETTING

Institutional level.

PARTICIPANTS

Ninety-seven athletes vaccinated only with the northern hemisphere vaccine; 98 athletes received the southern hemisphere vaccine alone, whereas 39 athletes were vaccinated with both vaccines.

INTERVENTIONS

The athletes were vaccinated with a trivalent, inactivated influenza vaccine recommended for the northern hemisphere 2015/2016 and then with the vaccine recommended for the southern hemisphere 2016. Athletes kept a diary of adverse events and effects (if any) on training for 6 days after vaccination.

MAIN OUTCOME MEASURES

The percentage of general and local adverse events, number of lost or modified training sessions.

RESULTS

Significantly more local adverse events (pain and redness) were found in the group immunized with the vaccine for the northern hemisphere. There were no differences in the frequency of general adverse events and influence on training between groups. Of total 273 athletes who had 1911 training days during 6 days after vaccination, 6 athletes (2.2%) lost 13 training days (0.7%) and 16 athletes (5.9%) had to modify 34 (1.7%) training days within first 2 days after vaccination.

CONCLUSIONS

Athletes tolerated influenza immunization well. If they are going to travel to the other hemisphere during the influenza season, the use of the second influenza vaccine should be advised. Athletes should anticipate modification of trainings for 2 days after vaccination.

Enhanced passive safety surveillance of a trivalent and a quadrivalent influenza vaccine in Denmark and Finland during the 2018/2019 season

The European Medicines Agency requires Enhanced Passive Safety Surveillance (EPSS) for all seasonal influenza vaccines. Here, we report the EPSS results for the trivalent inactivated influenza vaccine (IIV3; Vaxigrip®) and the quadrivalent inactivated influenza vaccine (IIV4; VaxigripTetra^TM) during the 2018/19 influenza season in Denmark and Finland. The primary objective was to estimate the rates of suspected adverse reactions (ARs) occurring within 7 days following routine vaccination. Between October and November 2018, 1000 safety report cards (SRCs) for IIV3 were distributed in Denmark, and 996 SRCs for IIV4 were distributed in Finland. Participants were instructed to report any ARs by telephone or e-mail using the information provided on the SRC. All participants vaccinated with IIV3 were aged ≥18 years. Most participants vaccinated with IIV4 (95.5%) were aged 18 − 65 years, 2.2% were aged 6 months to 17 years, and 2.3% were aged >65 years. Fifty-five ARs were reported by 12 participants (1.2%) vaccinated with IIV3 and 162 ARs were reported by 53 participants (5.3%) vaccinated with IIV4. The most frequent ARs were vaccination site pain and fever for IIV3, and vaccination site pain, vaccination site inflammation, myalgia, and headache for IIV4. The 2018/19 AR rates for IIV3 were comparable to 2017/18 rates. The 2018/19 AR rates for IIV4 were higher than those in 2017/18 but were still lower than the expected AR rates listed in the IIV4 Summary of Product Characteristics. In conclusion, the 2018/19 EPSS showed no clinically significant change from the expected safety profiles of IIV3 and IIV4 vaccines.

Active pharmacovigilance of the seasonal trivalent influenza vaccine produced by Instituto Butantan: A prospective cohort study of five target groups

Introduction

Active pharmacovigilance studies are pivotal to better characterize vaccine safety.

Methods

These are multicenter prospective cohort studies to evaluate the safety of the 2017 and 2018 seasonal trivalent influenza vaccines (TIVs) manufactured by Instituto Butantan, by means of active pharmacovigilance practices. Elderly, children, healthcare workers, pregnant women, and women in the puerperium period were invited to participate in the study during the 2017 and 2018 Brazilian national seasonal influenza vaccination campaigns. Following immunization, participants were observed for 30 minutes and they received a participant card to register adverse events information. All safety information registered were checked at a clinical site visit 14 days after immunization and by a telephone contact 42 days after immunization for unsolicited Adverse Events (AE) and Guillain-Barré Syndrome (GBS).

Results

A total of 942 volunteers participated in the two studies: 305 elderly, 109 children, 108 pregnant women, 32 women in the postpartum period, and 388 health workers. Overall, the median number of AR per participant ranged from 1 to 4. The lowest median number of AR per participant was observed among healthcare workers (1 AR per participant) and the highest among pregnant women (4 AR per participant). Overall, local pain (46.6%) was the most frequent solicited local AR. The most frequent systemic ARs were: headache (22.5%) followed by fatigue (16.0%), and malaise (11.0%). The majority of solicited ARs (96%) were mild, Grades 1 or 2), only 3% were Grade 3, and 1% was Grade 4. No serious AEs, including Guillain-Barré Syndrome, were reported up to 42 days postvaccination.

Conclusion

The results from the two studies confirmed that the 2017 and 2018 seasonal trivalent influenza vaccines produced by Instituto Butantan were safe and that active pharmacovigilance studies should be considered, when it is feasible, as an important initiative to monitor vaccine safety in the post-marketing period.

Quadrivalent influenza vaccine (Sinovac Biotech) for seasonal influenza prophylaxis

INTRODUCTION

Quadrivalent Influenza Vaccine (Sinovac Biotech) is a quadrivalent split-virion-inactivated influenza vaccine approved in China in June 2020 for individuals ≥3 years of age. It contains 15 µg hemagglutinin per strain including A/H1N1, A/H3N2, B/Victoria, and B/Yamagata, which could potentially improve protection against influenza B viruses.

AREAS COVERED

In this review, we summarize the development of quadrivalent influenza vaccines in China and foreign countries, and assess the immunogenicity and safety from the phase I and III clinical trials of Quadrivalent Influenza Vaccine in individuals ≥3 years of age. We also discuss the potential application of Quadrivalent Influenza Vaccine in young children 6-35 months of age according to the results of the phase III trial.

EXPERT COMMENTARY

The immunogenicity and safety profiles of Quadrivalent Influenza Vaccine containing two A and two B strains were comparable to the trivalent vaccines for the shared strains. The addition of a second B strain to the trivalent vaccine could induce superior immune responses for the alternate B strain. Since the two B strains co-circulated worldwide, the introduction of quadrivalent influenza vaccines has been expected to be a cost-effective strategy.

BanLec-eGFP Chimera as a Tool for Evaluation of Lectin Binding to High-Mannose Glycans on Microorganisms

Fluorescently labeled lectins are useful tools for in vivo and in vitro studies of the structure and function of tissues and various pathogens such as viruses, bacteria, and fungi. For the evaluation of high-mannose glycans present on various glycoproteins, a three-dimensional (3D) model of the chimera was designed from the crystal structures of recombinant banana lectin (BanLec, Protein Data Bank entry (PDB): 5EXG) and an enhanced green fluorescent protein (eGFP, PDB 4EUL) by applying molecular modeling and molecular mechanics and expressed in Escherichia coli. BanLec-eGFP, produced as a soluble cytosolic protein of about 42 kDa, revealed β-sheets (41%) as the predominant secondary structures, with the emission peak maximum detected at 509 nm (excitation wavelength 488 nm). More than 65% of the primary structure was confirmed by mass spectrometry. Competitive BanLec-eGFP binding to high mannose glycans of the influenza vaccine (Vaxigrip®) was shown in a fluorescence-linked lectin sorbent assay (FLLSA) with monosaccharides (mannose and glucose) and wild type BanLec and H84T BanLec mutant. BanLec-eGFP exhibited binding to mannose residues on different strains of Salmonella in flow cytometry, with especially pronounced binding to a Salmonella Typhi clinical isolate. BanLec-eGFP can be a useful tool for screening high-mannose glycosylation sites on different microorganisms.

Cost Utility of Switching From Trivalent to Quadrivalent Influenza Vaccine in Turkey

OBJECTIVES

Trivalent influenza vaccines (TIVs) are widely used but protect against only 1 of the 2 co-circulating influenza B virus lineages. Quadrivalent influenza vaccines (QIVs) include a B strain from each lineage to overcome mismatches. The main objective of this study was to determine the cost-utility and budget impact of switching from vaccination with TIV to QIV in the population recommended for influenza vaccination in Turkey.

METHODS

A static cohort cost-effectiveness model was developed to predict influenza-related costs and outcomes under a QIV versus a TIV program during an influenza season. The model was informed by data from Turkey on influenza strain distribution, influenza-attributable outcomes, and associated costs over the seasons 2010/2011 to 2016/2017. The effectiveness of each strategy was measured through quality-adjusted life-years (QALYs), and comparisons were based on the incremental cost-effectiveness ratio.

RESULTS

In an average influenza season, the model showed that switching from TIV to QIV would prevent an additional 15 092 cases of influenza, 6311 general practitioner visits, 94 hospitalizations, 13 deaths, and gain 440 QALYs. From the societal perspective, this amounted to total cost savings of international dollars (I$) 1102 710 (US$388 643). The incremental cost-effectiveness ratio when using QIV over TIV was I$55 248/QALY gained. Switching to QIV is mostly cost-effective among older adults with I$36 413.38/QALY. Sensitivity analysis showed that vaccine effectiveness, B strain mismatch, and influenza visits highly impact the cost-effectiveness results.

CONCLUSION

Switching from TIV to QIV is likely to be cost-effective in Turkey, yet highly dependent on the severity of the influenza season, B strain epidemiology, and vaccine effectiveness.

Attitudes of Nursing Home Staff Towards Influenza Vaccination: Opinions and Factors Influencing Hesitancy

Seasonal influenza is recognized to be a significant public health problem and a cause of death, especially in fragile persons. In nursing homes (NHs), vaccination for both residents and staff is the best preventive strategy. However, professionals' immunization rates are far from reaching the international recommended values. This study aims to describe the adherence and attitudes of NH staff towards flu vaccination and to explore staff hesitancy. A questionnaire was developed based on a literature review and on the 3Cs (confidence, complacency, convenience) of the WHO framework and administered among the staff of four NHs of a province in the northeast of Italy. Results demonstrated a low adherence towards annual vaccination (i.e., only 3% declared getting the flu vaccination each year). Complacency, confidence and convenience all showed a significant impact on the attitude towards vaccination both in univariate and multivariable analysis, with complacency being the most strongly associated area. The area of confidence resulted in strongly challenging factors. Only 24.8% of interviewees appeared trustful towards the efficacy of receiving immunization and 34% declared safety issues. Insights from the study can support the implementation of effective interventions to improve vaccination adherence in NHs. Specifically, increasing complacency by raising awareness related to the risks of influenza appears to be an essential strategy to effectively promote vaccination uptake.

Safety and immunogenicity of trivalent inactivated influenza vaccine in adults 60 years of age and older: a phase II, a randomized, comparative trial in Kazakhstan

BACKGROUND

The study was aimed at comparative evaluation of seasonal influenza vaccine RIBSP versus commercial vaccine VAXIGRIP® for immunogenicity and safety in the course of clinical trial phase II on healthy subjects up to 60 years.

METHODS

The trial involved 150 subjects in randomized 2:1 groups that received either RIBSP vaccine or comparator vaccine VAXIGRIP®. One dose (0.5 ml) of either vaccine contained 15 µg of hemagglutinin of each influenza virus strain recommended by WHO for the Northern hemisphere in 2016-2017 flu season. The observation period lasted 21 days. The trial was registered at ClinicalTrials.gov identifier NCT03016143.

RESULTS

Assessment of immunogenic activity of the vaccine under study showed that in 21 days the portion of participants with 4-fold seroconversions was 80.0% to А/H1N1; 65.0% to А/H3N2 and 64.0% to B virus. Antibody titer increase factor in the group of subjects that received RIBSP vaccine was 13.4 for А/H1N1; 5.2 for А/H3N2 and 5.2 for B virus. The subjects that received RIBSP vaccine demonstrated 88% seroprotection rate against А/H1N1; 75% against А/H3N2 and 61% against B virus. In the course of evaluating the vaccine safety, no serious adverse events were recorded. All changes of laboratory data were slight and single in most cases. All recorded local reactions have been light in character and these have been predicted reactions observed at vaccination against influenza.

CONCLUSION

Comparison vaccines RIBSP and VAXIGRIP®, showed similar immunogenic activity. The RIBSP vaccine is safe and immunogenic for the elderly and conforms to international criteria in CPMP/BWP/214/96.

A phase 2/3 double-blind, randomized, placebo-controlled study to evaluate the safety and immunogenicity of a seasonal trivalent inactivated split-virion influenza vaccine (IVACFLU-S) in healthy adults in Vietnam

Background: Under the WHO's Global Action Plan for influenza vaccines, we conducted a phase 2-3 study of IVACFLU-S, a trivalent, seasonal inactivated influenza vaccine candidate.Methods: In the phase 2 portion of the study, 252 participants received one dose of 15 mcg hemagglutinin (HA) vaccine per strain or placebo. Following determination of safety, 636 additional participants were randomized in phase 3 to receive vaccine or placebo. Immunogenicity was assessed in a subset of the participants in the phase 3 study.Results: Higher proportion (70%) of participants in the IVACFLU-S arm reported solicited local adverse events (AEs) (p < .0001) as compared to placebo (25%). Mild injection site pain and tenderness were most common AEs seen in 55% and 60% of participants in the vaccine group. The solicited systemic AEs were comparable (p = .4149). The majority of solicited and unsolicited AEs were mild to moderate in severity. In the vaccine arm for the combined age group of 18-60 years of age, seroconversion against antigens A/H1N1, A/H3N2, and B was achieved in 70.3%, 76.1%, and 54.1% of participants respectively; seroprotection against antigens A/H1N1, A/H3N2, and B was achieved in 83.3%, 86.6%, and 60.3% of participants respectively; and the geometric mean fold rise for the hemagglutinin-inhibition (HI) antibody titers against antigen A/H1N1, A/H3N2, and B were 13.15, 11.85, and 5.87, respectively.Conclusion: This study demonstrates the local reactogenicity, other safety, and immunogenicity of IVACFLU-S, first domestically produced influenza vaccine in Vietnam.ClinicalTrials.gov number NCT03095599 (March 29, 2017).

Enhanced passive safety surveillance of three marketed influenza vaccines in the UK and the Republic of Ireland during the 2017/18 season

Safety surveillance is required for each season’s influenza vaccines to rapidly detect and evaluate potential new safety concerns before the peak period of immunization. Here we report the results of an enhanced passive safety surveillance for a trivalent split-virion inactivated influenza vaccine (IIV3; Vaxigrip®), an intradermal version of this vaccine (IIV3-ID; Intanza® 15 µg), and a recently licensed quadrivalent version (IIV4; VaxigripTetra^TM) during the 2017/18 influenza season in the UK and Republic of Ireland. The primary objective was to determine the rates of adverse reactions (ARs) occurring within 7 days following routine vaccination. Between September and November 2017, 979 safety report cards were distributed to vaccinees receiving IIV3-ID, 1005 to those receiving IIV3, and 957 to those receiving IIV4. At least one AR was reported by 28 participants (2.9%) vaccinated with IIV3-ID, 14 participants (1.4%) vaccinated with IIV3, and 20 participants (2.1%) vaccinated with IIV4. The most frequent ARs were injection-site reactions and headache. One participant vaccinated with IIV3-ID reported two suspected serious ARs (dyskinesia and a shock symptom), although these could not be confirmed as vaccine-related. Rates of ARs for IIV3 and IIV3-ID for 2017/18 did not differ from the 2016/17 rates. For IIV4, in its first season since licensure, AR frequencies were similar to those in the Summary of Product Characteristics. In conclusion, no change was found compared to the known or expected AR rates for IIV3, IIV3-ID, or IIV4 during the 2017/18 season.

Adult Immunization - Need of the Hour

Immunization is the process of making individuals immune. Childhood immunization is a common process for various aliments, but adult immunization in the Indian scenario is obscure. Officially, India has been declared polio-free, which is an achievement despite cultural, political, economic, geographic, and so many other factors. The changing demographics of adult, geriatric population and growing cost of health-care maintenance are a concern in developing countries like India. Thus, promoting healthy lifestyle needs prevention, early detection, and management of various diseases and disorders. Certainly, prevention in adults is yet to be tapped completely, so that goal of 100% prevention can be achieved. Various fraternities of medical association have come up with guidelines for adult immunization schedules in India. The present paper reviews infectious diseases such as anthrax, chikungunya, cholera, dengue, influenza, and malaria in this section of the review. We humbly request all health-care professionals and educators to educate the mass for adult immunization. So that, cost involved for treatment and workforce for the management of diseases can be better utilized in some other needed areas.

[Quadrivalent influenza vaccine: What is changed and what are the benefits?]

Currently, circulating viruses responsible for annual seasonal influenza epidemics belong to two influenza A subtypes, A(H1N1) and A(H3N2), and to two antigenically distinct type B lineages, B/Yamagata and B/Victoria lineages. Like diseases due to influenza A virus, influenza B virus diseases may have severe consequences and should be prevented. Until now, in France, the vaccines used to prevent seasonal influenza were trivalent, systematically targeting viruses belonging to both A subtypes and to one or other of the B lineages. The protective efficacy of trivalent vaccines is diminished during the seasons when viruses belonging to both B lineages cocirculated or when the circulating dominant type B virus belonged to a lineage different from that targeted by the vaccine strain. By targeting viruses belonging to both B lineages, quadrivalent vaccines improve the antigenic concordance between circulating and vaccine type B strains. Three inactivated quadrivalent vaccines are authorized for marketing in France and should be available for the 2018-2019 season. It is expected that, by providing enlarged protection, these quadrivalent influenza vaccines will improve vaccine efficacy, the confidence in immunization of the public, the satisfaction of health professionals, and ultimately will help to complete immunization coverage.

Prospective cohort studies to evaluate the safety and immunogenicity of the 2013, 2014, and 2015 seasonal influenza vaccines produced by Instituto Butantan

Annual vaccination is the most effective way to prevent seasonal influenza illness. Instituto Butantan (IB) performed clinical studies with its 2013, 2014 and 2015 seasonal trivalent influenza vaccines (inactivated split-virion). Prospective cohort studies were carried out to describe the safety and immunogenicity of Instituto Butantan influenza vaccines, in healthy adults and elderly, from 2013 to 2015. Immediately after the informed consent was signed, participants underwent blood collection followed by vaccination. On study days 1, 2 and 3 post-vaccination participants were contacted by the staff to evaluate the occurrence of solicited (local and systemic) and non-solicited adverse reactions. On study day 21 (+7) subjects returned to the clinical site for final safety assessments and blood collection to evaluate post-vaccination immunogenicity. The immunogenicity analyses were performed by means of hemagglutination inhibition (HI) assay. The immunogenicity endpoints were: seroprotection (SPR) and seroconversion (SCR) rates and the geometric mean HI antibody titer ratio (GMTR). The 2013 study was conducted at the Centro de Referência para Imunobiológicos Especiais (CRIE) and at the Centro de Pesquisa Clínica do Instituto da Criança, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo while the 2014 and 2015 studies were conducted at CRIE. The vaccine composition followed the WHO recommendation for the Southern hemisphere seasonal influenza vaccine. Forty-seven healthy adults and 13 elderly participated in the 2013 study, 60 healthy adults and 60 elderly in the 2014 study, and 62 healthy adults and 57 elderly in the 2015 study. In the 2013, 2014 and 2015 studies, pain was the most frequent local adverse reaction and headache the most frequent systemic adverse reaction. All observed adverse reactions were classified as mild or moderate and none as severe. SPR >70% and SPR >60% were observed in adults and elderly, respectively, for the three vaccine viruses, in the 2013, 2014 and 2015 studies. SCR >40% was observed in adults, for the three vaccine viruses, only in the 2014 study and SCR >30% was observed in the elderly, for the three vaccine viruses, only in the 2013 and 2014 studies. GMTR >2.5 among adults, for the three vaccine viruses was only observed in the 2013 study and GMTR >2.0 was observed among elderly, for the three vaccine viruses, in the 2013, 2014 and 2015 studies. The 2013, 2014 and 2015 seasonal influenza vaccines produced by Instituto Butantan were safe and immunogenic according to the immunogenicity criteria defined by the European Medicines Agency (EMA).

Post-transplant Viral Respiratory Infections in the Older Patient: Epidemiology, Diagnosis, and Management

Organ and stem cell transplantation has been one of the greatest advances in modern medicine, and is the primary treatment modality for many end-stage diseases. As our population ages, so do the transplant recipients, and with that comes many new challenges. Respiratory viruses have been a large contributor to the mortality and morbidity of solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients. Respiratory viruses are generally a long-term complication of transplantation and primarily acquired in the community. With the emergence of molecular methods, newer respiratory viruses are being detected. Respiratory viruses appear to cause severe disease in the older transplant population. Influenza vaccine remains the mainstay of prevention in transplant recipients, although immunogenicity of current vaccines is suboptimal. Limited therapies are available for other respiratory viruses. The next decade will likely bring newer antivirals and vaccines to the forefront. Our goal is to provide the most up to date knowledge of respiratory viral infections in our aging transplant population.

Immunogenicity and safety of a novel seasonal influenza preservative-free vaccine manufactured in Kazakhstan: Results of a randomized, comparative, phase II clinical trial in adults

BACKGROUND

The study was aimed at comparative evaluation of seasonal influenza vaccine RIBSP versus commercial vaccine VAXIGRIP® for immunogenicity and safety in the course of clinical trial phase II on healthy volunteers aged 18-60 years.

METHODS

The trial involved 150 subjects in randomized 2:1 groups that received either RIBSP vaccine or comparator vaccine VAXIGRIP®. One dose (0.5 ml) of either vaccine contained 15 μg of hemagglutinin of each influenza virus strain recommended by WHO for the Northern hemisphere in 2016-2017 flu season. The observation period lasted 21 day. The trial was registered at ClinicalTrials.gov identifier NCT 03016143.

RESULTS

Assessment of immunogenic activity of the vaccine under study showed that in 21 day the portion of participants with 4-fold seroconversions was 87.0% to A/H1N1; 63.0% to A/H3N2 and 59.0% to B virus. Antibody titer increase factor in the group of subjects that received RIBSP vaccine was 23.3 for A/H1N1; 4.4 for A/H3N2 and 4.5 for B virus. The volunteers that received RIBSP vaccine demonstrated 95% seroprotection level against A/H1N1; 84% against A/H3N2 and 80% against B virus. RIBSP vaccine met the CHMP criteria of the Committee for Medicinal Products for Human Use (CPMP/BWP/214/96). In the course of evaluating the vaccine safety no serious undesirable effects were recorded. All changes of laboratory data were slight and single in most cases. All recorded local reactions have been light in character and these have been predicted reactions observed at vaccination against influenza.

CONCLUSION

Comparison of the allantoic inactivated split vaccine obtained in vaccines RIBSP and VAXIGRIP®, showed similar immunogenic activity. Both vaccines were safe for the study participants.

Quadrivalent inactivated influenza vaccine (VaxigripTetra™)

INTRODUCTION

VaxigripTetra™ (IIV4; Sanofi Pasteur) is a quadrivalent split-virion influenza vaccine approved in Europe in 2016 for individuals ≥ 3 years of age. IIV4 builds on the well-established record of the trivalent split-virion influenza vaccine (Vaxigrip®). Areas covered: This literature review summarizes the rationale for developing quadrivalent influenza vaccines and discusses the phase III clinical trial results supporting the immunogenicity, safety, and tolerability of IIV4. Expert commentary: IIV4 is immunogenic and well tolerated. Adding a second B strain to the trivalent split-virion influenza vaccine provides a superior immune response for the additional strain but does not reduce the immune response for the three other strains or negatively affect the safety profile. By offering broader protection against co-circulating influenza B lineages, IIV4 has the potential to further reduce influenza-related morbidity and mortality beyond that achieved with trivalent vaccines.