Cross-neutralizing antibodies to pandemic 2009 H1N1 and recent seasonal H1N1 influenza A strains influenced by a mutation in hemagglutinin subunit 2

Pandemic 2009 H1N1 influenza A virus (2009 H1N1) differs from H1N1 strains that circulated in the past 50 years, but resembles the A/New Jersey/1976 H1N1 strain used in the 1976 swine influenza vaccine. We investigated whether sera from persons immunized with the 1976 swine influenza or recent seasonal influenza vaccines, or both, neutralize 2009 H1N1. Using retroviral pseudovirions bearing hemagglutinins on their surface (HA-pseudotypes), we found that 77% of the sera collected in 1976 after immunization with the A/New Jersey/1976 H1N1 swine influenza vaccine neutralized 2009 H1N1. Forty five percent also neutralized A/New Caledonia/20/1999 H1N1, a strain used in seasonal influenza vaccines during the 2000/01-2006/07 seasons. Among adults aged 48-64 who received the swine influenza vaccine in 1976 and recent seasonal influenza vaccines during the 2004/05-2008/09 seasons, 83% had sera that neutralized 2009 H1N1. However, 68% of age-matched subjects who received the same seasonal influenza vaccines, but did not receive the 1976 swine influenza vaccine, also had sera that neutralized 2009 H1N1. Sera from both 1976 and contemporary cohorts frequently had cross-neutralizing antibodies to 2009 H1N1 and A/New Caledonia/20/1999 that mapped to hemagglutinin subunit 2 (HA2). A conservative mutation in HA2 corresponding to a residue in the A/Solomon Islands/3/2006 and A/Brisbane/59/2007 H1N1 strains that circulated in the 2006/07 and 2007/08 influenza seasons, respectively, abrogated this neutralization. These findings highlight a cross-neutralization determinant influenced by a point mutation in HA2 and suggest that HA2 may be evolving under direct or indirect immune pressure.     

The Canadian influenza decision, 1976.

This paper explains the Canadian decision process following the isolation and identification of A/New Jersey/8/76 at Fort Dix, New Jersey in February 1976. The cause for concern was the emergence of a swine-like strain related to that which caused the 1918-19 pandemic, together with proved man-to-man transmission. This concern was reinforced since all new influenza A strains known to have infected the number of persons involved at Fort Dix have become strains of epidemic importance. The Fort Dix outbreak gave sufficient warning to allow implementation of a national vaccination program, to prevent and protect against influenza. In the past such an opportunity had not occurred, and vaccine use had, at best, constituted an intervention in the course of an outbreak. The National Advisory Committee on Immunizing Agents had all available information when it reached its decision to recommend vaccination with bivalent (A/Victoria and A/New Jersey) or with monovalent (A/New Jersey) vaccine for selective, high-risk groups. This was an independent, scientifically based decision.     

Safety and immunogenicity of a monovalent MF59®-adjuvanted A/H1N1 vaccine in HIV-infected children and young adults

BackgroundThis Phase IV study evaluated the safety and immunogenicity of a two-dose, MF59^®-adjuvanted (Novartis Vaccines, Marburg, Germany), monovalent, A/H1N1 pandemic influenza vaccination schedule in Human Immunodeficiency Virus (HIV) positive children and young adults.MethodsA total of 83 children infected with HIV-1, and 37 non-immunocompromised, age-matched controls were enrolled. All participants received two vaccine doses administered three weeks apart. Antibody responses were assessed by haemagglutination assay at baseline, three weeks after each vaccine dose, and six months after immunization. Vaccines were evaluated according to European influenza vaccine licensure criteria.ResultsThe investigational vaccine was well tolerated. After the first vaccine dose, seroconversion rates were significantly lower in HIV-positive patients (60%) than controls (82%), with GMTs of 419 and 600, respectively. No significant differences in seroconversion rates were observed between the two study groups in response to the second vaccine dose. Persisting antibody titers were similar for both HIV-positive and non-infected controls, six months after immunization.ConclusionOne dose of MF59-adjuvanted vaccine was sufficient to provide adequate levels of seroprotection against A/H1N1 influenza disease in HIV-positive children. However, a two-dose vaccination schedule may be optimal for this population.     

INFLUENZA VACCINE,ASIAN STRAIN—Reactions Following Its Use in Adults

A study of reactions following influenza vaccine inoculation of 327 employees of Peralta Hospital, 55 men and 272 women, showed a very low value for significant or severe reactions. The reaction rate as observed with the present monovalent vaccine containing 200 CCA units of Asian strain, Type A influenza virus, was considerably lower than that reported with previous polyvalent vaccines containing up to 1,400 or 1,500 CCA units of total virus content.The absenteeism rate was 1.1 per cent for women, nil for men.The incidence of reactions was much greater in women than in men. Local reactions such as pain, swelling, or redness at the site of injection occurred in 29.1 per cent of men and 35.7 per cent of women. The incidence of systemic reactions—fever, aching, chilliness, headache, nausea and vomiting—was 3.6 per cent in men and 8.8 per cent in women. About 9 per cent of men and 30 per cent of women had both local and systemic reaction. Some 58 per cent of men and 25 per cent of women had no reaction.The greater majority of reactions appeared within five hours after inoculation with influenza vaccine.In adults the prevention of anaphylactic reactions due to the small amount of egg protein in influenza vaccine, can be accomplished by screening for history of hypersensitivity to egg, chicken or chicken feather. In questionable cases, intradermal testing can be done.The reaction rate observed in this study for the present influenza vaccine was so low that it ought not deter immunization.     

Surveillance of the swine influenza vaccination program at the Royal Military College,Kingston.

In a prospective study symptoms appearing in a previously healthy population within 6 weeks after inoculation with monovalent swine influenza vaccine (A/New Jersey/76) were tabulated. Of the 703 persons (ranging in age from 17 to 55 years) participating in the follow-up 54% reported experiencing symptoms, usually within 24 hours of vaccination; the symptoms were usually minor and none of the participants displayed evidence of Guillain-Barré syndrome.     

Persistence of influenza serum antibodies in humans following immunization with a bivalent A/Victoria and A/New Jersey vaccine.

The persistence of serum antibodies 1 year after immunization with a bivalent vaccine containing recombinant viruses that were antigenically identical with A/Victoria/3/75 (H3N2) and A/New Jersey/8/76 (Hsw1N1) viruses was measured in 128 persons aged 18 to 65 years. Serum samples were tested with the hemagglutination inhibition assay against the two vaccine antigens and against A/Texas/1/77 (H3N2) and A/USSR/90/77 (H1N1) viruses. Prior to vaccination 56% and 79% of the participants had been found to be seronegative to A/Victoria and A/New Jersey antigens respectively; the geometric mean antibody titres were low (1:5 to 1:11) except in persons aged 51 to 65 years, whose mean titre of antibody to the A/New Jersey antigen was 1:23, and persons aged 26 to 35 years, whose mean titre of antibody to the A/USSR antigen was 1:25. By 3 weeks after vaccination 85% of the seronegative persons had a fourfold or greater rise in titres of antibodies to the viruses in the vaccine, and 70% had a fourfold increase in titre of antibody to the A/Texas antigen. Of the persons aged 26 to 35 years (seronegative and seropositive) 68% had a fourfold or greater increase in titre of antibody to the A/USSR antigen. There was no change in the mean titres of 19 unvaccinated control subjects during the observation period. At 6 and 12 months after vaccination the titres of antibodies to the A/Victoria and A/New Jersey antigens had declined moderately in all age groups from those observed 3 weeks after vaccination. The rate of decline was similar for the various antibodies except that to the A/USSR antigen in persons 26 to 35 years of age, in whom the decline was much slower.     

Immunogenicity of inactivated seasonal influenza vaccine in adult and pediatric liver transplant recipients over two seasons

Immunological responses to influenza vaccination administered to liver transplantation recipients are not fully elucidated. To compare inactivated influenza vaccine's immunogenicity between adult and pediatric recipients, 16 adult and 15 pediatric living donor liver transplantation recipients in the 2010–11 influenza season, and 53 adult and 21 pediatric recipients in the 2011–12 season, were investigated. Seroprotection rates (hemagglutinin‐inhibition [HI] antibody titer 1:40) were 50–94% to all three antigens among adults and 27–80% among children in both seasons. Seroconversion rates (fourfold or more HI antibody rise) were 32–56% among adults and 13–67% among children in both seasons. No significant differences were observed between the two groups. In addition, 20/53 adult and 13/21 pediatric recipients received a vaccine containing identical antigens in both of these seasons. Geometric mean titer fold increases of all three antigens in adult recipients were significantly lower than those in recipients who had not received a preceding vaccination. In contrast, in pediatric recipients, there were no significant differences between the groups who had and had not received preceding vaccinations. The number of patients with rejection did not differ significantly between the two groups (0/53 vs. 1/21) in the 2011–12 season. The incidence of influenza after vaccination was significantly different between adult and pediatric recipients (0/16 vs. 5/15 in 2010–11 and 0/53 vs. 3/21 in 2011–12, respectively). Overall, there were no significant differences in antibody responses between adult and pediatric groups. Influenza infection was more frequent in pediatric recipients. Long‐term response to preceding vaccinations appeared to be insufficient in both groups.     

Phase I evaluation of intranasal trivalent inactivated influenza vaccine with nontoxigenic Escherichia coli enterotoxin and novel biovector as mucosal adjuvants, using adult volunteers

Trivalent influenza virus A/Duck/Singapore (H5N3), A/Panama (H3N2), and B/Guandong vaccine preparations were used in a randomized, controlled, dose-ranging phase I study. The vaccines were prepared from highly purified hemagglutinin and neuraminidase from influenza viruses propagated in embryonated chicken eggs and inactivated with formaldehyde. We assigned 100 participants to six vaccine groups, as follows. Three intranasally vaccinated groups received 7.5-microg doses of hemagglutinin from each virus strain with either 3, 10, or 30 microg of heat-labile Escherichia coli enterotoxin (LTK63) and 990 microg of a supramolecular biovector; one intranasally vaccinated group was given 7.5-microg doses of hemagglutinin with 30 microg of LTK63 without the biovector; and another intranasally vaccinated group received saline solution as a placebo. The final group received an intramuscular vaccine containing 15 microg hemagglutinin from each strain with MF59 adjuvant. The immunogenicity of two intranasal doses, delivered by syringe as drops into both nostrils with an interval of 1 week between, was compared with that of two inoculations by intramuscular delivery 3 weeks apart. The intramuscular and intranasal vaccine formulations were both immunogenic but stimulated different limbs of the immune system. The largest increase in circulating antibodies occurred in response to intramuscular vaccination; the largest mucosal immunoglobulin A (IgA) response occurred in response to mucosal vaccination. Current licensing criteria for influenza vaccines in the European Union were satisfied by serum hemagglutination inhibition responses to A/Panama and B/Guandong hemagglutinins given with MF59 adjuvant by injection and to B/Guandong hemagglutinin given intranasally with the highest dose of LTK63 and the biovector. Geometric mean serum antibody titers by hemagglutination inhibition and microneutralization were significantly higher for each virus strain at 3 and 6 weeks in recipients of the intramuscular vaccine than in recipients of the intranasal vaccine. The immunogenicity of the intranasally delivered experimental vaccine varied by influenza virus strain. Mucosal IgA responses to A/Duck/Singapore (H5N3), A/Panama (H3N2), and B/Guandong were highest in participants given 30 microg LTK63 with the biovector, occurring in 7/15 (47%; P=0.0103), 8/15 (53%; P=0.0362), and 14/15 (93%; P=0.0033) participants, respectively, compared to the placebo group. The addition of the biovector to the vaccine given with 30 microg LTK63 enhanced mucosal IgA responses to A/Duck/Singapore (H5N3) (P=0.0491) and B/Guandong (P=0.0028) but not to A/Panama (H3N2). All vaccines were well tolerated.     

H7N9灭活疫苗联合MF59佐剂在小鼠体内诱导的长效体液免疫应答

以BALB/c小鼠为模型,探讨H7N9流感病毒灭活疫苗免疫小鼠后所诱导的长效体液免疫应答的动态变化。不同剂量的流感H7N9全病毒灭活疫苗单独或辅以MF59佐剂肌肉注射免疫小鼠一次。连续采集免疫后小鼠15个月的血清,用ELISA方法检测特异性IgG抗体水平,血凝抑制(hemagglutination inhibition,HI)试验和微量中和(microneutralization,MN)试验检测第15个月时的HI抗体和中和抗体效价。实验结果发现,小鼠血清中的特异性IgG抗体水平随时间变化持续缓慢上升,第5个月时达到顶峰,随后略有下降但一直持续平稳状态;IgG抗体滴度与疫苗剂量成正相关,且添加佐剂能提高抗体滴度。HI及MN抗体检测表明,免疫后第15个月产生的抗体能有效中和病毒,且抗体跟疫苗剂量成正比。以上研究表明,H7N9流感病毒灭活疫苗免疫小鼠一次诱导产生的特异性抗体能在较长期内保持比较平稳的抗体滴度,为小鼠提供免疫保护;增加抗原剂量和添加MF59佐剂能增加疫苗特异性抗体水平。该研究为H7N9流感疫苗产生的长期保护效应提供了一定的数据积累和参考。     

Effects of iron deficiency upon the antibody response to influenza virus in rats

The effects of severe and moderate iron deficiency upon the antibody response to influenza virus were investigated in rats. Three groups of weanling male Wistar rats were fed one of two iron-deficient diets (5 mg and 15 mg iron/kg diet) or a normal iron-containing diet (35 mg iron/kg diet). A group of individually pair-fed rats was introduced with the low iron-consuming rats. The effects of the diets upon various iron status parameters were followed during the 4th, 5th, 6th, and 7th week of diet. After 4 weeks of feeding different diets, an intraperitoneal injection of inactivated influenza virus A/New Jersey/76 was performed and a recall injection was done at 5 weeks. Primary and secondary antibody responses were assayed. Rats were sacrificed at 7 weeks of diet. After 4 weeks of feeding different diets, the rats fed the 5 mg iron/kg diet were severely anemic and rats fed 15 mg iron/kg diet were moderately iron-deficient, as shown by their iron status parameters. Growth was delayed in anemic and matched pair-fed rats. A primary antibody response was almost nonexistent in all groups. Secondary antibody titers were significantly weaker in anemic rats than in ad libitum controls, but were not different from those of pair-fed rats. This response was similar in moderately iron-deficient, ad libitum, and pair-fed rats. These results show that antibody synthesis in response to the influenza virus vaccine is preserved in moderate iron deficiency but is reduced in severe anemia. The reduction in energy consumption associated with severe iron deficiency in the rat could play a part in the altered humoral response.     

Single immunization with MF59-adjuvanted inactivated whole-virion H7N9 influenza vaccine provides early protection against H7N9 virus challenge in mice

H7N9 influenza infection in humans would result in severe respiratory illness. Vaccination is the best way to prevent influenza virus. In this paper, we investigated the effect of early protection provided by inactivated whole-virion H7N9 influenza vaccine in a mouse model.Mice were immunized intramuscularly once with different doses of inactivated whole-virion H7N9 influenza vaccine alone or in combination with MF59 adjuvant. Specific IgM and IgG antibody titers in sera of mice were detected by ELISA 3, 5 and 7days after immunization. To evaluate the early protection provided by the vaccine, mice were challenged with lethal dose (40LD₅₀) of homologous virus 3, 5 and 7 days after immunization respectively. The survival rate and body weight change of mice during 21 days after challenge and the residual lung virus titer on 3rd day after challenge were determined. The results demonstrated that mice could obtain effective protection 3 days after immunization with the vaccine at a high dose, and 5–7 days after immunization even at a low dose. Thus early immune responses induced by inactivated whole-virion H7N9 vaccine could provide effective protection.     

Influence of prior influenza vaccination on antibody and B-cell responses

Currently two vaccines, trivalent inactivated influenza vaccine (TIV) and live attenuated influenza vaccine (LAIV), are licensed in the USA. Despite previous studies on immune responses induced by these two vaccines, a comparative study of the influence of prior influenza vaccination on serum antibody and B-cell responses to new LAIV or TIV vaccination has not been reported. During the 2005/6 influenza season, we quantified the serum antibody and B-cell responses to LAIV or TIV in adults with differing influenza vaccination histories in the prior year: LAIV, TIV, or neither. Blood samples were collected on days 0, 7-9 and 21-35 after immunization and used for serum HAI assay and B-cell assays. Total and influenza-specific circulating IgG and IgA antibody secreting cells (ASC) in PBMC were detected by direct ELISPOT assay. Memory B cells were also tested by ELISPOT after polyclonal stimulation of PBMC in vitro. Serum antibody, effector, and memory B-cell responses were greater in TIV recipients than LAIV recipients. Prior year TIV recipients had significantly higher baseline HAI titers, but lower HAI response after vaccination with either TIV or LAIV, and lower IgA ASC response after vaccination with TIV than prior year LAIV or no vaccination recipients. Lower levels of baseline HAI titer were associated with a greater fold-increase of HAI titer and ASC number after vaccination, which also differed by type of vaccine. Our findings suggest that the type of vaccine received in the prior year affects the serum antibody and the B-cell responses to subsequent vaccination. In particular, prior year TIV vaccination is associated with sustained higher HAI titer one year later but lower antibody response to new LAIV or TIV vaccination, and a lower effector B-cell response to new TIV but not LAIV vaccination.     

Characteristics of the clinical and immunologic safety of inactivated influenza vaccines in children undergoing multiple immunizations

In a strictly controlled epidemiological trial on 12,643 school children aged 11-14 years the reactogenic properties and safety of killed influenza chromatographic vaccine under the conditions of multiple immunization were studied. A single immunization dose of the vaccine (0.2 ml) contained the hemagglutinins of influenza viruses A/Philippines/82 (H3N3) and A/Kiev/59/79 (H1N1), 3.5 micrograms each. The preparation was introduced by means of a jet injector. The vaccine was shown to be clinically and immunologically safe under the conditions of the regular multiple immunization of children over the period of 4 years.     

Immunogenicity and cross-reactivity of 2009-2010 inactivated seasonal influenza vaccine in US adults and elderly

The campaign of 2009-2010 Northern Hemisphere seasonal vaccination was concurrent with the 2009 H1N1 pandemic. Using a hemagglutination inhibition (HAI) assay, we evaluated the immunogenicity and cross-reactivity of 2009-2010 inactivated trivalent influenza vaccine (TIV) in US adult and elderly populations. Vaccination of TIV resulted in a robust boost on the antibody response of all subjects to seasonal A/Brisbane/59/2007 (H1N1) and A/Uruguay/716/2007 (H3N2) with over 70% of recipients reaching a seroprotective titer of 40. B/Brisbane/60/2008 was the least immunogenic among the three seasonal vaccine strains with <30% of TIV recipients reaching a seroprotective titer of 40. TIV vaccination also induced a moderate boost on the pandemic specific antibody responses. Twenty-four percent of adults and 36% of elderly reached a seroprotective HAI titer of 40 or more against pandemic A/South Carolina/18/2009 (H1N1) after receiving TIV compared to 4% and 7% at the beginning of vaccination, respectively. In addition, 22% of adults and 34% of elderly showed an increase of 4-fold or more in A/South Carolina/18/2009 specific HAI titers after TIV vaccination. The pandemic specific cross-reactive antibodies strongly correlated with the post-vaccination HAI titers against the seasonal H3N2 vaccine strain in all subjects.     

Fatal outcome of pandemic H1N1 2009 influenza virus infection is associated with immunopathology and impaired lung repair, not enhanced viral burden, in pregnant mice

Pandemic A (H1N1) 2009 influenza virus (pH1N1) infection in pregnant women can be severe. The mechanisms that affect infection outcome in this population are not well understood. To address this, pregnant and nonpregnant BALB/c mice were inoculated with the wild-type pH1N1 strain A/California/04/09. To determine whether innate immune responses are associated with severe infection, we measured the innate cells trafficking into the lungs of pregnant versus nonpregnant animals. Increased infiltration of pulmonary neutrophils and macrophages strongly correlated with an elevated mortality in pregnant mice. In agreement with this, the product of nitric oxide (nitrite) and several cytokines associated with recruitment and/or function of these cells were increased in the lungs of pregnant animals. Surprisingly, increased mortality in pregnant mice was not associated with higher virus load because equivalent virus titers and immunohistochemical staining were observed in the nasal cavities or lungs of all mice. To determine whether exacerbated inflammatory responses and elevated cellularity resulted in lung injury, epithelial regeneration was measured. The lungs of pregnant mice exhibited reduced epithelial regeneration, suggesting impaired lung repair. Despite these immunologic alterations, pregnant animals demonstrated equivalent percentages of pulmonary influenza virus-specific CD8(+) T lymphocytes, although they displayed elevated levels of T-regulator lymphocytes (Tregs) in the lung. Also, pregnant mice mounted equal antibody titers in response to virus or immunization with a monovalent inactivated pH1N1 A/California/07/09 vaccine. Therefore, immunopathology likely caused by elevated cellular recruitment is an implicated mechanism of severe pH1N1 infection in pregnant mice.     

Immunization with a Live Attenuated H7N9 Influenza Vaccine Protects Mice against Lethal Challenge

The emergence of severe cases of human influenza A (H7N9) viral infection in China in the spring of 2003 resulted in a global effort to rapidly develop an effective candidate vaccine. In this study, a cold-adapted (ca), live attenuated monovalent reassortant influenza H7N9 virus (Ah01/AA ca) was generated using reverse genetics that contained hemagglutinin (HA) and neuraminidase (NA) genes from a 2013 pandemic A H7N9 isolate, A/Anhui/01/2013 virus (Ah01/H7N9); the remaining six backbone genes derived from the cold-adapted influenza H2N2 A/Ann Arbor/6/60 virus (AA virus). Ah01/AA ca virus exhibited temperature sensitivity (ts), ca, and attenuation (att) phenotypes. Intranasal immunization of female BALB/c mice with Ah01/AA ca twice at a 2-week interval induced robust humoral, mucosal, and cell-mediated immune responses in a dose-dependent manner. Furthermore, the candidate Ah01/AA ca virus was immunogenic and offered partial or complete protection of mice against a lethal challenge by the live 2013 influenza A H7N9 (A/Anhui/01/2013). Protection was demonstrated by the inhibition of viral replication and the attenuation of histopathological changes in the challenged mouse lung. Taken together, these data support the further evaluation of this Ah01/AA ca candidate vaccine in primates.     

Induction of interferon in man by vaccines.

The purpose of this study was to extend the spectrum of vaccines with interferon-inducing potential in man. The vaccines selected for study were the commercially available attenuated poliomyelitis vaccine type 2 (Sabin strain) and the new live attenuated influenza A/England/42/72 (H3N2) vaccine ("Alice" strain). Five subjects, two of whom had low or undetectable polio type 2 neutralizing antibody levels were given the type 2 vaccine (10-4.7 TCID50) in the standard manner orally. Even though the two individuals with low titers experienced a fourfold or greater antibody rise and one of them shed the virus in his stool, neither they nor the remaining three volunteers developed detectable levels of interferon in their sera obtained at very closely spaced intervals from day 0 to day 25 following immunization. Fifteen subjects were given approximately 10-7.5 TCID50 of influenza A/England/42/72 (H3N2) by nasal drops. Specimens consisting of sera and nasal washings were obtained at closely timed intervals for 23 days, starting with day 3 following immunization. Interferon could be detected in three of nine (33.3%) subjects who had fourfold or greater HI antibody rises. No interferon was detected in nasal washings, however. It is concluded that poliomyelitis is not a good interferon inducers in man. Live attenuated influenza vaccine does induce an interferon response in subjects with low initial serum antibody titers. This response is at best modest. The latter finding also suggests that the attenuation of the Alice strain of influenza A vaccine is not dependent on its interferon inducing potential.     

Immune protection induced on day 10 following administration of the 2009 A/H1N1 pandemic influenza vaccine

Background

The 2009 swine-origin influenza virus (S-OIV) H1N1 pandemic has caused more than 18,000 deaths worldwide. Vaccines against the 2009 A/H1N1 influenza virus are useful for preventing infection and controlling the pandemic. The kinetics of the immune response following vaccination with the 2009 A/H1N1 influenza vaccine need further investigation.

Methodology/Principal Findings

58 volunteers were vaccinated with a 2009 A/H1N1 pandemic influenza monovalent split-virus vaccine (15 µg, single-dose). The sera were collected before Day 0 (pre-vaccination) and on Days 3, 5, 10, 14, 21, 30, 45 and 60 post vaccination. Specific antibody responses induced by the vaccination were analyzed using hemagglutination inhibition (HI) assay and enzyme-linked immunosorbent assay (ELISA). After administration of the 2009 A/H1N1 influenza vaccine, specific and protective antibody response with a major subtype of IgG was sufficiently developed as early as Day 10 (seroprotection rate: 93%). This specific antibody response could maintain for at least 60 days without significant reduction. Antibody response induced by the 2009 A/H1N1 influenza vaccine could not render protection against seasonal H1N1 influenza (seroconversion rate: 3% on Day 21). However, volunteers with higher pre-existing seasonal influenza antibody levels (pre-vaccination HI titer ≥1∶40, Group 1) more easily developed a strong antibody protection effect against the 2009 A/H1N1 influenza vaccine as compared with those showing lower pre-existing seasonal influenza antibody levels (pre-vaccination HI titer <1∶40, Group 2). The titer of the specific antibody against the 2009 A/H1N1 influenza was much higher in Group 1 (geometric mean titer: 146 on Day 21) than that in Group 2 (geometric mean titer: 70 on Day 21).

Conclusions/Significance

Recipients could gain sufficient protection as early as 10 days after vaccine administration. The protection could last at least 60 days. Individuals with a stronger pre-existing seasonal influenza antibody response may have a relatively higher potential for developing a stronger humoral immune response after vaccination with the 2009 A/H1N1 pandemic influenza vaccine.     

Recombinant Parainfluenza Virus 5 Vaccine Encoding the Influenza Virus Hemagglutinin Protects against H5N1 Highly Pathogenic Avian Influenza Virus Infection following Intranasal or Intramuscular Vaccination of BALB/c Mice

New approaches for vaccination to prevent influenza virus infection are needed. Emerging viruses, such as the H5N1 highly pathogenic avian influenza (HPAI) virus, pose not only pandemic threats but also challenges in vaccine development and production. Parainfluenza virus 5 (PIV5) is an appealing vector for vaccine development, and we have previously shown that intranasal immunization with PIV5 expressing the hemagglutinin from influenza virus was protective against influenza virus challenge (S. M. Tompkins, Y. Lin, G. P. Leser, K. A. Kramer, D. L. Haas, E. W. Howerth, J. Xu, M. J. Kennett, J. E. Durbin, R. A. Tripp, R. A. Lamb, and B. He, Virology 362:139–150, 2007). While intranasal immunization is an appealing approach, PIV5 may have the potential to be utilized in other formats, prompting us to test the efficacy of rPIV5-H5, which encodes the HA from H5N1 HPAI virus, in different vaccination schemes. In the BALB/c mouse model, a single intramuscular or intranasal immunization with a live rPIV5-H5 (ZL46) rapidly induced robust neutralizing serum antibody responses and protected against HPAI challenge, although mucosal IgA responses primed by intranasal immunization more effectively controlled virus replication in the lung. The rPIV5-H5 vaccine incorporated the H5 HA into the virion, so we tested the efficacy of an inactivated form of the vaccine. Inactivated rPIV5-H5 primed neutralizing serum antibody responses and controlled H5N1 virus replication; however, similar to other H5 antigen vaccines, it required a booster immunization to prime protective immune responses. Taken together, these results suggest that rPIV5-HA vaccines and H5-specific vaccines in particular can be utilized in multiple formats and by multiple routes of administration. This could avoid potential contraindications based on intranasal administration alone and provide opportunities for broader applications with the use of a single vaccine vector.     

Perspectives of immunization program managers on 2009-10 H1N1 vaccination in the United States: a national survey

In June and July 2010, we conducted a national internet-based survey of 64 city, state, and territorial immunization program managers (IPMs) to assess their experiences in managing the 2009-10 H1N1 influenza vaccination campaign. Fifty-four (84%) of the managers or individuals responsible for an immunization program responded to the survey. To manage the campaign, 76% indicated their health department activated an incident command system (ICS) and 49% used an emergency operations center (EOC). Forty percent indicated they shared the leadership of the campaign with their state-level emergency preparedness program. The managers' perceptions of the helpfulness of the emergency preparedness staff was higher when they had collaborated with the emergency preparedness program on actual or simulated mass vaccination events within the previous 2 years. Fifty-seven percent found their pandemic influenza plan helpful, and those programs that mandated that vaccine providers enter data into their jurisdiction's immunization information system (IIS) were more likely than those who did not mandate data entry to rate their IIS as valuable for facilitating registration of nontraditional providers (42% vs. 25%, p<0.05) and tracking recalled influenza vaccine (50% vs. 38%, p<0.05). Results suggest that ICS and EOC structures, pandemic influenza plans, collaborations with emergency preparedness partners during nonemergencies, and expanded use of IIS can enhance immunization programs' ability to successfully manage a large-scale vaccination campaign. Maintaining the close working relationships developed between state-level immunization and emergency preparedness programs during the H1N1 influenza vaccination campaign will be especially important as states prepare for budget cuts in the coming years.