The adjuvanted influenza vaccines with novel adjuvants: experience with the MF59-adjuvanted vaccine

Elderly people and subjects with underlying chronic diseases are at increased risk for influenza and related complications. Conventional influenza vaccines provide only limited protection in the elderly population. In order to enhance the immune response to influenza vaccines, several adjuvants have been evaluated. Among these, an oil in water adjuvant emulsion containing squalene, MF59, has been combined with subunit influenza antigens and tested in clinical trials in comparison with non-adjuvanted conventional vaccines. Data from a clinical database of over 10000 elderly subjects immunised with this adjuvanted vaccine (Fluad, Chiron Vaccines, Siena, Italy) demonstrate that, although common postimmunisation reactions are more frequent in recipients of the adjuvanted vaccine, this vaccine is well tolerated, also after re-immunisation in subsequent influenza seasons. Immunogenicity analyses demonstrate a consistently higher immune response with statistically significant increases of postimmunisation geometric mean titres, and of seroconversion and seroprotection rates compared to non-adjuvanted subunit and split influenza vaccines, particularly for the A/H3N2 and the B strains. The higher immunogenicity profile of the MF59-adjuvanted vaccine is maintained also after subsequent immunisations. An even higher adjuvant effect was shown in subjects with low pre-immunisation titre and in those affected by chronic underlying diseases. In conclusion, the addition of MF59 to subunit influenza vaccines enhances significantly the immune response in elderly subjects without causing clinically important changes in the safety profile of the influenza vaccine.     

Safety and immunogenicity of MF59-adjuvanted influenza vaccine in the elderly

Safety and immunogenicity of the influenza vaccine adjuvanted with MF59 (FLUAD) were compared to those of a non adjuvanted subunit vaccine in elderly subjects during three consecutive influenza seasons. Geometric mean titres and proportions of subjects with either a > or = four-fold increase in antibody titres or with an HI titre > or = 128 after immunisation were higher in FLUAD recipients. The adjuvant effect on the magnitude of the responses was most pronounced in subjects with pre-vaccination titres < or = 40. Although associated with more frequent mild local reactions, the adjuvanted vaccine was well tolerated. Thus, the addition of MF59 increased the immunogenicity of the subunit influenza vaccine in elderly persons with low pre-vaccination titres, who are at greatest risk of developing severe influenza disease and vaccine failure, without a clinically important increase in reactogenicity.     

Antibody induction by virosomal, MF59-adjuvanted, or conventional influenza vaccines in the elderly

In a randomized, observer-blind, three-arm, parallel group, multi-centre trial including 386 elderly subjects in four countries, the immunogenicity and safety was studied of three different trivalent inactivated surface antigen (subunit) influenza vaccine types: a conventional subunit influenza vaccine (SIV, brand: Influvac and two newer vaccines: a MF59-adjuvanted subunit influenza vaccine (adSIV, brand: Fluad and a virosomal subunit influenza vaccine (vSIV, brand: Invivac. All vaccines were trivalent containing 15 microg hemagglutinin of each virus strain as recommended by the World Health Organization for the 2004-2005 season. The study was designed to demonstrate the serological non-inferiority of vSIV to both adSIV and SIV in elderly persons. The secondary objective was to investigate whether vSIV is superior to adSIV with respect to local reactogenicity. For all three vaccine strains, the post-vaccination geometric mean titres were comparable between SIV and adSIV and between vSIV and SIV. Seroprotection rates (i.e. percentages of subjects with a post-vaccination titre >or=40) varied between 84.1-100% indicating that the three vaccines all induced a strong antibody response. Local and systemic reactions were more frequently associated with adSIV (46 and 32%, respectively) than with vSIV or SIV ( approximately 20%). Vaccinations caused only little inconvenience as measured by questionnaire. In general, all vaccines were safe and well tolerated. In this trial, virosomal vaccine had similar immunogenicity to MF59-adjuvanted and conventional subunit vaccine and was considerably less reactogenic than the MF59-adjuvanted vaccine in the elderly.     

MF59-佐剂流感亚单位疫苗在中国老年人中的免疫原性和安全性研究

目的 比较MF59-佐剂流感亚单位疫苗与传统的非佐剂流感亚单位疫苗在老年人中的安全性和免疫原性.方法 采用随机、研究者设盲的对照研究,按照2:1的比例分别给予600名60岁以上老年人接种MF-59佐剂流感亚单位疫苗(复立达TM,简称佐剂流感疫苗)和传统的非佐剂流感亚单位疫苗(爱阁力保(R),简称传统亚单位疫苗),观察接种日和接种后7天内的局部反应和全身反应;使用血凝抑制试验检测接种老年人免疫前后的血凝抑制抗体(HI)滴度,计算基线无免疫保护状态受试者的抗体4倍增长阳转率、免疫后HI抗体达到保护水平(≥1:40)的保护率以及抗体GMT值和增长倍数.比较两者在安全性和免疫原性的差异.结果 两组疫苗的局部反应和全身反应相似,但传统亚单位疫苗组(n=200)中注射部位的硬结相对常见(P＜0.05),而佐剂流感疫苗组(n=400)中注射部位轻度疼痛和发热则相对较常见.对于基线无免疫保护状态的受试者,免疫后针对A/H3N2病毒株的抗体阳转率,佐剂流感疫苗组显著高于传统亚单位疫苗组(P＜0.001);除A/H1N1病毒株外,与基线相比,两组疫苗的保护率均有显著提高,但针对A/H3N2病毒株的保护率方面,佐剂流感疫苗显著高于传统亚单位疫苗(P＜0.001);两组疫苗接种后的GMT均比基线明显增加(P＜0.001),但佐剂流感疫苗组明显高于传统亚单位疫苗组.结论 中国老年人对佐剂流感疫苗耐受性良好,佐剂流感疫苗诱导的免疫原性水平比传统亚单位疫苗高,可使免疫力低下的老年人获益更大.     

Immunogenicity and safety of a 13-valent pneumococcal conjugate vaccine and an MF59-adjuvanted influenza vaccine after concomitant vaccination in ⩾60-year-old adults

BackgroundConcomitant administration of influenza and pneumococcal vaccines could be an efficient strategy to increase vaccine uptake among older adults. Nevertheless, immune interference and safety issues have been a concern when more than one vaccines are administered at the same time.MethodsSubjects aged ⩾60 years were randomized in a 1:1:1 ratio to receive MF59-adjuvanted trivalent inactivated influenza vaccine (MF59-aTIV) + 13-valent pneumococcal conjugate vaccine (PCV13) (Group 1), PCV13 alone (Group 2), or MF59-aTIV alone (Group 3). Hemagglutination inhibition (HI) and opsonophagocytic activity (OPA) assays were used to compare immunogenicity after single or concomitant vaccination.ResultsA total of 1149 subjects (Group 1, N = 373; Group 2, N = 394; Group 3, N = 382) were available for the assessment of immunogenicity and safety. All groups met immunogenicity criteria for the influenza vaccine in older adults with similar seroprotection rates, seroconversion rates, and geometric mean titer (GMT) fold-increases, irrespective of concomitant vaccination. For each pneumococcal serotype, OPA titers increased markedly after the PCV13 vaccination, irrespective of the concomitant influenza vaccination. After concomitant administration, the non-inferiority criteria of GMT ratios were met for all three influenza subtypes and 13 pneumococcal serotypes. No vaccine-related serious adverse events occurred.ConclusionsConcomitant MF59-aTIV and PCV13 administration showed no interference with antibody response and showed good safety profiles.(Clinical Trial Number – NCT02215863).     

Increased immunogenicity of the MF59-adjuvanted influenza vaccine compared to a conventional subunit vaccine in elderly subjects

Three-hundred and eight outpatient elderly subjects ( 65 years) were randomly assigned to receive the MF59-adjuvanted influenza vaccine (FLUAD; n = 204) or a conventional subunit influenza vaccine (AGRIPPAL S1; n = 104) in order to compare the safety and immunogenicity of the two vaccines. Although mild pain at the injection site was reported more frequently by subjects immunised with the adjuvanted vaccine, both vaccines were shown to be safe and well tolerated. The adjuvanted vaccine was more immunogenic as indicated by higher post-immunisation geometric mean titres (GMTs) and by higher proportions of subjects with post-immunisation four fold increases of antibody titres or subjects with 1/160 post-immunisation HI titres. These differences, statistically significant for all three strains after immunisation, indicated that, by addition of the MF59 adjuvant emulsion, conventional subunit influenza antigens acquire an enhanced immunogenicity without any clinically significant increase of their reactogenicity.     

Antibody response against heterogeneous circulating influenza virus strains elicited by MF59- and non-adjuvanted vaccines during seasons with good or partial matching between vaccine strain and clinical isolates

MF59 is already known to enhance the breadth of antibody response to mismatched influenza seasonal and avian strains. However, little is known on the effect of MF59 on immunogenicity of influenza vaccines when “apparent” good matching between circulating and vaccine strains exists. To this end, we compared the immune response elicited by MF59-adjuvanted or non-adjuvanted subunit vaccine, containing A/California/7/04(H3N2) strain, against circulating viruses isolated between 2004/2005 and 2006/2007 seasons, belonging to different clades. The advantage offered by MF59 in terms of higher immunogenicity, expressed as higher post-vaccination HI titres, is observable also against viruses showing antigenic and molecular pattern undistinguishable from vaccine strain, but it became even more evident as the antigenic and molecular distance between vaccine and circulating strains grew. These data show that seasonal influenza vaccine adjuvanted with MF59 can offer a stronger benefit as compared to non-adjuvanted vaccine in protecting against a broader range of virus strains circulating during the influenza season.     

Cross-protection by MF59-adjuvanted influenza vaccine: neutralizing and haemagglutination-inhibiting antibody activity against A(H3N2) drifted influenza viruses

Adjuvants enhance antibody response against vaccination. We compared the ability of MF59-adjuvanted and non-adjuvanted subunit influenza vaccines, containing A/Wyoming/3/03(H3N2), to confer cross-protection against four consecutive drifted strains in the elderly. Neutralizing and haemagglutination-inhibiting antibody were measured. MF59-adjuvanted vaccine induced a stronger booster response against A/Panama/2007/99(H3N2) than non-adjuvanted vaccine. A/Panama/2007/99(H3N2) circulated widely during the previous 5 years and was included in vaccines over four consecutive seasons. Broader serological protection against drifted strains that circulated 1 and 2 years after vaccination with A/Wyoming/3/03(H3N2) was observed with MF59-adjuvanted vaccine. Thus, MF59-adjuvanted vaccine confers greater immunogenicity than non-adjuvanted vaccines in vulnerable populations.     

Impact of corticosteroids on the immune response to a MF59-adjuvanted influenza vaccine in elderly COPD-patients

The influence of steroids on the antibody response to a MF59-adjuvanted influenza vaccine in elderly COPD patients has not been studied previously. In the influenza season 2001/02 (October-February) elderly COPD patients were recruited at 14 doctor's offices and our 250-bed hospital. Patients were stratified into three groups according to current treatment regimen: (a) > 10 mg of prednisolone/day (SS); (b) inhaled steroids (IS); (c) no steroid treatment (control group, CG). All patients were vaccinated with the MF59-adjuvanted influenza vaccine. Antibodies against the influenza strains A/H1N1, A/H3N2, and B were measured at baseline, 4 and 24 weeks after vaccination by hemagglutination inhibition (HI) assay. One-hundred and sixty-two patients completed the study (CG n = 42; IS n = 87; SS n = 33). Mean age was 71.3 years (range 60-89). Twenty-one percent of all patients reported local reactions; no serious adverse events were observed. Four weeks after vaccination, mean geometric HI titres (GMT) for A/H1N1, A/H3N and B increased significantly in all groups (p < or = 0.05). After 24 weeks, GMTs to A/H1N1 and A/H3N2 returned to baseline, while GMTs to type B remained significantly higher than baseline in all groups. Significant differences between the groups as regards GMTs, seroconversion (56-89%) or seroprotection rates (64-93%) were not observed. Systemic steroids did not influence the antibody response towards the MF59-adjuvanted influenza vaccine. We found that the strains included in the vaccine showed varying long-term immunogenicity.     

流行性感冒灭活亚单位疫苗和裂解疫苗的安全性和免疫原性的比较研究

目的：比较流感亚单位疫苗与裂解疫苗的安全性和免疫原性。方法：流感亚单位疫苗和裂解疫苗按随机双盲法分别接种249名和250名6～12岁健康儿童。于接种当日和接种后3天内观察局部反应和全身反应。用血凝抑制试验检测接种儿童免疫前后的血凝抑制抗体(HI)滴度，计算抗体4倍增长阳转率，免疫后的保护水平抗体(≥1：40)的免疫成功率，以及抗体几何平均滴度((GMT)值和增长倍数。比较流感亚单位疫苗和裂解疫苗的临床观察结果。结果：两种疫苗接种后均未见局部反应，发热反应率和中高度发热反应率亚单位疫苗低于裂解疫苗，两组的差异有显著的统计学意义。未见其他全身反应。对疫苗3个毒株的血清学检测结果显示：亚单位疫苗的阳转率为74．5％～95．1％，保护水平抗体的免疫成功率为94．2％～99．6％，抗体GMT增长倍数为5．4～21．2。裂解疫苗的阳转率为79．8％～97．8％，保护水平抗体的免疫成功率为96．4％～100．0％，抗体GMT、增长倍数为6．4～21．0。两种疫苗的免疫学效果相似，所见差异无显著的统计学意义。结论：流感亚单位疫苗和裂解疫苗接种6～12岁儿童后反应轻微，安全性良好，亚单位疫苗发热反应率低于裂解疫苗。两种疫苗的免疫原性良好，具有同样显著的免疫效果，可以推广使用。     

Evaluation of safety and immunogenicity of HNVAC,an MDCK-based H1N1 pandemic influenza vaccine,in Phase I single centre and Phase II/III multi-centre,double-blind,randomized, placebo-controlled,parallel assignment studies

The clinical evaluation of the MDCK-based H1N1 pandemic influenza vaccine HNVAC in adults aged 18–65 years is reported. In the Phase I randomized, double-blind, placebo-controlled, single-centre study, 160 subjects were parallelly assigned 3:1 to vaccine:placebo groups (n = 60:20) with both the aluminium hydroxide adjuvanted and non-adjuvanted vaccine formulations. A single dose of both the formulations containing 15 μg of haemagglutinin protein showed minimal adverse reactions, the most common of which were pain at injection site (11.67%) and fever (10.00%). Both formulations produced 74–81% seroprotection (SRP: titre of ≥40), 67–70% seroconversion (SRC: four-fold increase in titres between days 0 and 21), and a four-fold increase in geometric mean titres (GMT). Aluminium hydroxide did not have a significant effect either on immunogenicity or on reactogenicity. Nevertheless, based on its recognized positive effects on the stability and immunogenicity of many vaccines, and its marginal benefit in both pre-clinical and Phase I studies of HNVAC, alum adjuvanted HNVAC was further tested in a staggered Phase II/III randomized, double-blind, placebo-controlled, multi-centre study of 200 and 195 subjects, respectively, parallelly assigned 4:1 to adjuvanted vaccine and placebo groups. In these studies, the most common adverse reactions were pain at injection site (6.88% and 5.77% in Stage 1 and Stage 2, respectively) and fever (7.50% and 7.05%, respectively), and a single dose resulted in 87–90% SRP, 85–86% SRC, and a nearly six-fold increase in GMT, meeting or exceeding licensing criteria. It is concluded that HNVAC is safe and immunogenic to adults of 18–65 years.     

Safety and immunogenicity of an MF59(®)-adjuvanted A/H5N1 pre-pandemic influenza vaccine in adults and the elderly

Background

The potential consequences of an avian influenza pandemic warrants the development of safe, highly immunogenic pre-pandemic A/H5N1 vaccines with cross-clade protection. In this randomized, controlled study we compared the immunogenicity and safety of an MF59^®-adjuvanted (Novartis Vaccines, Marburg, Germany) A/H5N1 pre-pandemic vaccine with that of a licensed, MF59-adjuvanted, seasonal influenza vaccine.

Methods

Healthy adult (18–60 years, n = 3372) and elderly (≥61 years, n = 275) volunteers received either an initial dose of a licensed, non-adjuvanted, trivalent, seasonal influenza vaccine (Agrippal^®) on Day 1, followed by one dose of MF59-H5N1 study vaccine on Day 22 and a second dose of MF59-H5N1 on Day 43, or alternatively, placebo on Day 1 followed by one dose of MF59-adjuvanted seasonal reference vaccine on Day 22 and a second dose of reference vaccine on Day 43. Homologous and cross-reactive A/H5N1 antibody responses were analysed by haemagglutination inhibition (HI), single radial haemolysis (SRH), and microneutralization (MN) assays three weeks after each vaccination. Vaccine safety was assessed throughout the study.

Results

Analysis by HI assay found that two doses of MF59-H5N1 resulted in a seroconversion rate of 56% and a geometric mean ratio (GMR) of 7.1 in adult subjects. Similar results were observed on analysis by SRH (GMR 4.03; seroconversion 78% and seroprotection 91%) and MN (seroconversion 67%) assays. These data met the European licensure criteria for influenza vaccines. No significant difference in immunogenicity was detected between the adult and elderly populations. Anti-A/H5N1 cross-clade antibodies were detected by SRH, 49% of adult and 32% of elderly subjects achieved seroconversion after the second vaccine dose. Overall, MF59-H5N1 containing 7.5 μg antigen was less reactogenic than the MF59-adjuvanted trivalent seasonal vaccine which contained 15 μg antigen for each component strain.

Conclusions

Two doses of MF59-H5N1 vaccine were well tolerated and induced adequate levels of seroprotection against homologous and cross-clade A/H5N1 virus. These data support the suitability of MF59-adjuvanted A/H5N1 vaccine for pre-pandemic use in adults and the elderly.     

A randomized, controlled study in adults of the immunogenicity of a novel hepatitis B vaccine containing MF59 adjuvant.

The safety and immunogenicity of a novel hepatitis B virus (HBV) vaccine containing recombinant PreS2 and S antigens combined with MF59 adjuvant (HBV/MF59) was evaluated in healthy adults (N=230) who were randomized to receive 2 or 3 immunizations of either the study vaccine or a licensed control vaccine (Recombivax HB). After a single immunization, 105 of 118 (89%) recipients of HBV/MF59 achieved protective serum levels of anti-HBs antibody (> 10 mIU/ml), compared with 13 of 110 (12%) recipients of licensed vaccine (P < 0.001). The geometric mean titer (GMT) after 2 doses of HBV/MF59 given 2 months apart (13,422 mIU/ml) was more than 5-fold higher than that following 3 doses of licensed vaccine given over 6 months (2,346 mIU/ml; P < 0.001). The GMT following 3 injections of HBV/MF59 (249,917 mIU/ml) was 100-fold higher than licensed vaccine (P < 0.001). Anti-PreS2 antibodies were elicited in over 90% of the subset of HBV/MF59 recipients tested. Both vaccines were well tolerated; transient, mild-to-moderate local inflammation was the major postinjection reaction.     

Pandemic influenza A/H1N1 vaccine administered sequentially or simultaneously with seasonal influenza vaccine to HIV-infected children and adolescents

In order to evaluate the immunogenicity, safety and tolerability of the 2009 A/H1N1 MF59-adjuvanted influenza vaccine administered sequentially or simultaneously with seasonal virosomal-adjuvanted influenza vaccine to HIV-infected children and adolescents, 36 HIV-infected children and adolescents, and 36 age- and gender-matched healthy controls were randomised 1:1 to receive the pandemic vaccine upon enrolment and the seasonal vaccine one month later, or to receive the pandemic and seasonal vaccines simultaneously upon enrolment. Seroconversion and seroprotection rates against the pandemic influenza A/H1N1 virus were 100% two months after vaccine administration in both groups, regardless of the sequence of administration. Geometric mean titres against pandemic and seasonal antigens were significantly higher when the seasonal and pandemic vaccines were administered simultaneously than when the seasonal vaccine was administered alone. Local and systemic reactions were mild and not increased by simultaneous administration. In conclusion, the 2009 pandemic influenza A/H1N1 MF59-adjuvanted vaccine is as immunogenic, safe and well tolerated in HIV-infected children and adolescents as in healthy controls. Its simultaneous administration with virosomal-adjuvanted seasonal antigens seems to increase immune response to both pandemic and seasonal viruses with the same safety profile as that of the pandemic vaccine alone. However, because this finding cannot be clearly explained by an immunological viewpoint, further studies are needed to clarify the reasons of its occurrence.     

Long-lasting immunogenicity of a virosomal vaccine in older children and young adults with type I diabetes mellitus

To evaluate the long-lasting immunogenicity and reactogenicity of a virosomal influenza vaccine in subjects with type I diabetes, a trial was conducted during the 2007–2008 influenza season in Milan, Northern Italy. One hundred five subjects aged 9–30 years were randomized to receive by intramuscular injection vaccination by a single dose (0.5 ml) of either a virosomal (Inflexal V^®) (n = 52) or a standard subunit (Influvac^®) (n = 53) vaccine. Serum hemagglutinin inhibition antibody titres were determined against the three recommended influenza-like strains, A/H1N1, A/H3N2 and B, at pre-vaccination, and 1 and 6 months post-vaccination. Geometric mean titres were increased in the two groups 1 and 6 months post-vaccination (P < 0.001). One month post-vaccination both vaccines met the CPMP requirement for immunogenicity with high seroprotection rates (>95%) for strains A/H1N1 and A/H3N2, and a seroprotection of 73% and 70% in the virosomal and subunit vaccine for strain B. Mean fold increase ranged 2.8 (A/H3N2)–6.2 (A/H1N1) in the virosomal group and 2.3 (A/H3N2)–4.8 (A/H1N1) in the subunit group. Immunogenicity declined 6 months post-vaccination in both groups, and the CPMP requirement for immunogenicity was satisfied only in the virosomal group. In subjects without pre-existing antibodies to strain B (titre <10), the virosomal vaccine showed higher immune response than the subunit vaccine 6 months post-vaccination, with a geometric mean titre (95% CI) of 40.2 (30.7–54.6) vs. 21.2 (14.6–30.8). Reactogenicity was similar in the two vaccines. All reactions were transient and not severe. The results indicate that in older children and young adults with type I diabetes influenza vaccination with a virosomal or a standard subunit vaccine is safe and adequately immunogenic against the three influenza vaccine strains. In addition, the virosomal vaccine may show better long-lasting immune response than the standard subunit vaccine, especially in subjects without pre-existing antibodies to influenza strains.     

An indirect comparison meta-analysis of AS03 and MF59 adjuvants in pandemic influenza A(H1N1)pdm09 vaccines

BackgroundAlthough oil-in-water adjuvants improve pandemic influenza vaccine efficacy, AS03 versus MF59 adjuvant comparisons in A(H1N1)pdm09 pandemic vaccines are lacking.MethodsWe conducted an indirect-comparison meta-analysis extracting published data from randomised controlled trials in literature databases (01/01/2009–09/09/2018), evaluating immunogenicity and safety of AS03- or MF59-adjuvanted vaccines. We conducted comparisons of log-transformed haemagglutination inhibition geometric mean titre ratio (GMTR; primary outcome) of different regimens of each adjuvant versus unadjuvanted counterparts. Then via test of subgroup differences, we indirectly compared different AS03 versus MF59 regimens.ResultsWe identified 22 publications with 10,734 participants. In adults, AS03-adjuvanted vaccines (3.75 µg haemagglutinin) achieved superior GMTR versus unadjuvanted vaccines (all four comparisons); MD = 0.56 (95%CI 0.33 to 0.80, p < 0.001) to 1.18 (95%CI 0.72 to 1.65, p < 0.001). MF59 (full-dose)-adjuvanted vaccines (7.5 µg haemagglutinin) were superior to unadjuvanted vaccines (three of four comparisons); MD = 0.47 (95%CI 0.19 to 0.75, p = 0.001) to 0.80 (95%CI 0.44 to 1.16, p < 0.001). Adult indirect comparisons favoured AS03 over MF59 (six of eight comparisons; p < 0.001 to p = 0.088).Paediatric indirect comparisons favoured MF59-adjuvanted vaccines (two of seven comparisons; p = 0.011, 0.079). However, unadjuvanted control group seroconversion rate was lower in MF59 than AS03 studies (p < 0.001 to p = 0.097).There was substantial heterogeneity, and adult AS03 studies had lower risk of bias.ConclusionsDespite limited studies, in adults, AS03-adjuvanted vaccines allow antigen sparing versus MF59-adjuvanted and unadjuvanted vaccines, with similar immunogenicity, but higher risk of pain and fatigue (secondary outcomes) than unadjuvanted vaccines. In children, adjuvanted vaccines are also superior, but the better adjuvant is uncertain.     

Comparison of the reactogenicity and immunogenicity of a split and a subunit-adjuvanted influenza vaccine in elderly subjects

A randomised, open study was carried out among an elderly population in order to compare the reactogenicity and immunogenicity of an inactivated, split virion influenza vaccine (Vaxigrip, Aventis Pasteur MSD, Lyon, France) with that of an MF59-adjuvanted, subunit vaccine (Fluad, Chiron Vaccines, Siena, Italy). Both vaccines contained the three strains: A/Sydney/5/97 (H3N2), A/Beijing/262/95 (H1N1) and B/Beijing/184/93, recommended by the WHO for the 1998-1999 influenza season. A total of 2150 subjects were vaccinated and included in the reactogenicity analysis. A total of 1076 subjects received Vaxigrip (age 73.3 +/- 5.9 years, 49.6% men) and 1074 subjects received Fluad (age 73.4 +/- 5.9 years, 52.3% men). All subjects were kept under medical observation for 30 min after vaccination, in order to check any immediate local and/or systemic reaction. A self monitoring diary card was given to all subjects to collect any local and/or systemic reaction occurring during the 3 days following the vaccination, any adverse event occurring between vaccination day and 21st day post-vaccination and any medication taken during the study period. A total of 1186 subjects were included in the immunogenicity analysis. A total of 591 subjects received Vaxigrip (age 73.4 +/- 5.6 years, 52.3% men) and 595 subjects received Fluad (age 73.8 +/- 5.9 years, 55.8% men). Blood samples were collected pre- and 21 days post-vaccination and were analysed by the haemagglutination inhibition assay. In terms of reactogenicity both vaccines were generally well tolerated. The frequency of local reactions was lower in the group that received Vaxigrip. Pain at the injection site occurring from 30 min to 3 days after vaccination was also significantly less frequent (P = 0.005) in the Vaxigrip group. Fever > or =37.5 degrees C was reported in less than 1% of all vaccinated subjects. No serious adverse event was related to vaccine administration. In terms of immunogenicity both vaccines induced an effective immune response (anti-HI titre > or =40) against A/Sydney/5/97 (H3N2) and A/Beijing/262/95 (H1N1) strains in the entire population. Vaxigrip and Fluad induced similar seroprotection and seroconversion rates against the A/Sydney/5/97 (H3N2) strain. For both vaccines a lower percentage of subjects achieved a seroprotective titre > or =40 against the B/Beijing/184/93. A lower antibody response against the influenza B strain was also observed in other studies conducted during the same season. In subjects 75 years of age or older, Fluad was more immunogenic than Vaxigrip for all three virus strains.     

Safety and immunogenicity of adjuvanted and unadjuvanted subunit influenza vaccines administered intranasally to healthy adults

Antigen-specific mucosal immunity is thought to be important for protection against influenza virus infection. Currently licensed parenteral influenza vaccines stimulate the production of serum antibodies, but are poor inducers of mucosal immunity. The adjuvant MF59 has been shown to enhance the humoral immune response to parenteral influenza vaccine in humans and the mucosal immune response to intranasally-administered influenza vaccine in mice. We conducted an open-label safety study followed by an observer-blind, randomized trial comparing the immune response to intranasally-administered subunit influenza vaccine adjuvanted with MF59, unadjuvanted subunit influenza vaccine, and placebo. Adverse reactions did not occur significantly more frequently in vaccinees than placebo recipients. Of 31 subjects receiving 2 doses of MF59-adjuvanted influenza vaccine, 19 (61%), 8 (26%), and 11 (35%) developed a mucosal IgA response to influenza A/H1N1, A/H3N2, and B, respectively. The percentage of subjects with a serum antibody response was slightly lower. The immune responses to adjuvanted vaccine were not significantly different from those to unadjuvanted vaccine. Both vaccines gave more frequent responses than seen in placebo recipients, indicating the potential of intranasal inactivated vaccines to stimulate local IgA responses.     

Influenza vaccines: Antibody responses to split virus and MF59-adjuvanted subunit virus in an adult population

The humoral immune response generated by two commercial influenza vaccines was evaluated in a randomised, double-blind trial performed in the Public Department of Dolo Health District (North-east Italy) during the winter season 1997–1998. Ninety-eight subjects were immunised with a split virus vaccine and ninety-six with a MF59-adjuvanted subunit virus vaccine (SU/MF59). The pre- and postvaccination (30 days) antibody titres were determined by hemagglutination inhibition test (HI). After immunisation protective titre rates ( 1:40) were near 100% against virus A strain and 82.5% against B strain. Both vaccines caused significant rises in geometric mean antibody titres (GMTs); however, people who received SU/MF59 vaccine were found to develop a greater immune response compared to the group immunised with SVV. According to logistic regression analysis the unprotective prevaccination immune status and the use of SU/MF59 were identified as independent factors significantly increasing the response to immunisation.     

MF59-adjuvanted influenza vaccine (FLUAD) in children: Safety and immunogenicity following a second year seasonal vaccination

After priming with two intramuscular doses of MF59^®-adjuvanted (Sub/MF59) or split influenza vaccines during the 2006/07 season, 89 healthy children received a third booster dose of the respective vaccine (2007/08 Northern Hemisphere formulation) approximately 1 year later, and were followed up for 6 months post-third injection. Immunogenicity was evaluated on 81 of them by a hemagglutination inhibition (HI) assay before and 3 weeks after vaccination.