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Abstract: Currently, more than half of the world''s population has no immunity against smallpox variola major virus. This phase I double-blind, randomized trial was conducted to compare the safety and immunogenicity of two clonally derived, cell-culture manufactured vaccinia strains, ACAM1000 and ACAM2000, to the parent vaccine, Dryvax®. Thirty vaccinia-naïve subjects were enrolled into each of three groups and vaccines were administered percutaneously using a bifurcated needle at a dose of 1.0×108 PFU/mL. All subjects had a primary skin reaction indicating a successful vaccination. The adverse events, 4-fold neutralizing antibody rise and T cell immune responses were similar between the groups. [Copyright &y& Elsevier]

Abstract: Smallpox vaccination with replication deficient vaccinia strains such as Modified Vaccinia Ankara (MVA) may induce protective immunity with improved safety and tolerability profiles compared with currently available smallpox vaccines. Ninety subjects were randomized equally to six groups in a partially blinded, randomized, controlled clinical trial. IMVAMUNE® (MVA-BN®, Bavarian Nordic A/S, Kvistgård, Denmark) vaccine or placebo was administered at Study Days 0 and 28 by subcutaneous or intramuscular injection and five groups were challenged with Dryvax® at study Day 112. Vaccination with two doses of IMVAMUNE® was safe and well tolerated compared to Dryvax®. IMVAMUNE® produced comparable cellular and humoral immune responses to one dose of Dryvax® and the immunity induced appears robust 90 days post-vaccination by evidence of attenuated primary cutaneous reaction responses following Dryvax®. IMVAMUNE® vaccination prior to Dryvax® reduced virus replication at the Dryvax® site, decreased the size of the primary cutaneous lesion, and decreased the time to healing but did not completely ameliorate the immune response. [Copyright &y& Elsevier]

Abstract: The present study was undertaken with controls using equal doses ID and IM plus the standard full dose IM to assess the role of route of vaccine in immunogenicity of inactivated influenza vaccine. The study was a prospective, randomized, active-controlled, open label clinical trial conducted in healthy young adult outpatients to compare the effect of route (IM versus ID) on antibody responses to influenza vaccine. Volunteers received 3, 6 or 9μg of vaccine by ID or IM route; 15μg IM was also studied. Low doses of vaccine given by either route were almost as immunogenic as the standard 15μg IM dose of influenza vaccine. ID route was not superior to IM vaccine at inducing antibodies. ID vaccine induced significantly more local inflammatory response than IM vaccine. [Copyright &y& Elsevier]

We evaluated a combination respiratory syncytial virus (RSV) and parainfluenza 3 virus (PIV3) live, attenuated intranasal vaccine for safety, viral replication, and immunogenicity in doubly seronegative children 6-18 months old. RSV cpts-248/404 and PW3-cp4S vaccines were combined in a dose of 105 plaque-forming units of each per 0.5-mL dose and compared with monovalent vaccines or placebo. The virus shedding pattern of RSV was not different between monovalent RSV cpts-2481404 vaccine and combination vaccine. Modest reductions in the shedding of PIV3-cp45 vaccine virus were found after the administration of RSV cpts-2481404 and PIV3-cp45 vaccine, relative to monovalent PIV3 vaccine; 16 (76%) of 21 children given combination vaccine shed PIV3- cp45 versus 11 (92%) of 12 of those given monovalent PIV3 vaccine. Both vaccines were immunogenic, and antibody responses were similar between the monovalent groups and the combination group. Combined RSV/PV3 vaccine is feasible for simultaneous administration, and further studies are warranted. [ABSTRACT FROM AUTHOR]

A phase 2 evaluation of live attenuated parainfluenza type 3 (PIV3)­cold passage mutant 45 (cp45) vaccine was conducted in 380 children 6–18 months old; 226 children (59%) were seronegative for PIV3. Of the 226 seronegative children, 114 received PIV3-cp45 vaccine, and 112 received placebo. No significant difference in the occurrence of adverse events (i.e., runny nose, cough, or temperature ≤38 °C) was noted during the 14 days after vaccination. There was no difference between groups in the occurrence of acute otitis media or serous otitis media. Paired serum samples were available for 109 of the seronegative vaccine recipients and for 110 of the seronegative placebo recipients; 84% of seronegative vaccine recipients developed a ≥4-fold increase in antibody titers. The geometric mean antibody titer after vaccination was 1:25 in the vaccine group and <1:4 in the placebo group. PIV3-cp45 vaccine was safe and immunogenic in seronegative children and should be evaluated for efficacy in a phase 3 field trial. [ABSTRACT FROM AUTHOR]

To evaluate the humoral immune responses to smallpox-vaccine stocks currently available in the United States (Dry-vax; Wyeth) and to generate data for comparison of responses to newly produced lots of smallpox vaccine, we evaluated dose-response effects, using undiluted and diluted smallpox vaccine. At 28 and 56 days after vaccination, serum samples were obtained from vaccinated subjects (N = 674) who had participated in a randomized, single-blinded trial of an undiluted or a 1:5 or 1:10 dilution of smallpox vaccine and who subsequently were tested for plaque-reduction neutralizing-antibody titer. All subjects who developed a vesicle after vaccination also developed neutralizing antibodies by day 28. Subjects given either a 1:5 or 1:10 dilution of vaccinia had significantly higher neutralizing-antibody titers than did subjects given undiluted vaccine. Larger lesion size and fever after vaccination were associated with significantly higher neutralizing-antibody titers after vaccination. [ABSTRACT FROM AUTHOR]

Context: There is renewed interest in use of smallpox vaccine due to the potential for a bioterrorist attack. This would involve vaccinating health care workers who were previously vaccinated. Objective: To evaluate the use of diluted vaccinia virus in vaccination of previously vaccinated (non-naive) participants. Design, Setting, and Participants: Eighty non-naive participants, aged 32 to 60 years, were randomized in a single-blinded study to receive either undiluted or diluted (1:3.2, 1:10, or 1:32) doses of smallpox vaccine. A comparison group, aged 18 to 31 years, of 10 vaccinia-naive participants received undiluted vaccine. Participants were enrolled between April 1 and May 15, 2002, at the National Institute of Allergy and Infectious Diseases Vaccine and Treatment Evaluation Unit at Saint Louis University, St Louis, Mo. Intervention: Smallpox vaccine was administered by scarification using 15 skin punctures in the deltoid region of the arm. Main Outcome Measures: Presence of a major reaction, defined as a vesicular or pustular lesion or area of palpable induration surrounding a central lesion following vaccination, and measures of viral shedding and antibody titers. Results: Initial vaccination resulted in a major reaction in 64 of 80 non-naive participants. Ninety-five percent of non-naive participants had major reactions in the undiluted group, 90% in the 1:3.2 dilution group, 81% in the 1:10 dilution group, and 52.6% in the 1:32 dilution group. All (n = 10) of the vaccinia-naive participants had major reactions. Compared with vaccinia-naive participants, non-naive participants had significantly smaller skin lesions (P = .04) and significantly less incidence of fever (P = .02). Preexisting antibody was present in 76 of 80 non-naive participants. Antibody responses were significantly higher and occurred more rapidly in the non-naive participants compared with the vaccinia-naive participants (P = .002 for day 28 and P = .003 for 6 months). Vaccinia-naive... [ABSTRACT FROM AUTHOR]

Examines the stability of Dryvax virus vaccine to determine whether diluted vaccine could be used over an extended period, thereby increasing the number of available doses. Stability parameters; Dilution; Diluent; Temperature; Effects of storage of reconstituted Dryvax vaccine at room temperature, regardless of dilution or diluent.

Background: If found to be safe and immunogenic, reduced doses of influenza vaccine given by the intradermal route could increase the number of available doses of vaccine. Methods: In an open-label study, we randomly assigned 119 subjects to receive an intradermal injection of trivalent inactivated influenza vaccine, containing 6 μg of hemagglutinin for each antigen (40 percent of the usual dose), and 119 to receive an intramuscular injection of the standard dose of 15 μg of hemagglutinin for each antigen. The two groups were subdivided according to age (18 to 60 years and older than 60 years). Results: Among subjects who were 18 to 60 years of age, serum antibody responses were vigorous and did not differ significantly between the intradermal and intramuscular groups, and all subjects had hemagglutination-inhibition (HAI) titers of at least 1:40. Although the subjects who were older than 60 years of age also had a vigorous antibody response, there was a trend toward a better response in the intramuscular route, but this finding was significant only for antigen to the H3N2 strain. Nevertheless, 100 percent of older subjects in the intramuscular group and 93 percent of such subjects in the intradermal group had an HAI antibody titer to the H3N2 strain of more than 1:40, and 100 percent in each group had a titer of this level for both the H1N1 and B strains. Local pain was significantly more common in the intramuscular group than in the intradermal group among subjects who were 18 to 60 years of age but not among subjects who were over 60 years old. Signs of local inflammation were significantly more common among subjects in the intradermal group than among those in the intramuscular group, in both age groups. Conclusions: As compared with an intramuscular injection of full-dose influenza vaccine, an intradermal injection of a reduced dose resulted in similarly vigorous antibody responses among persons 18 to 60 years of age but not among those over the age of 60 years. N Engl J Med 2004;351:2286-94. [ABSTRACT FROM AUTHOR]

Background: We conducted a double-blind, randomized trial of three dilutions of vaccinia virus vaccine in previously unimmunized adults in order to assess the clinical success rates, humoral responses, and virus-specific activity of cytotoxic T cells and interferon-γ–producing T cells. Methods: Sixty healthy adults were inoculated intradermally by bifurcated needle with undiluted vaccine (dose, 107.8 plaque-forming units [pfu] per milliliter), a 1:10 dilution (dose, 106.5 pfu per milliliter), or a 1:100 dilution (dose, 105.0 pfu per milliliter); there were 20 subjects in each group. The subjects were monitored with respect to vesicle formation (an indicator of successful vaccination), the viral titer at the time of peak lesion formation, antiviral antibodies, and cellular immune responses. Results: A vaccinia vesicle developed in 19 of the 20 subjects who received undiluted vaccine (95 percent), 14 of the 20 who received the 1:10 dilution (70 percent), and 3 of the 20 who received the 1:100 dilution (15 percent). One month after vaccination, 34 of 36 subjects with vesicles had antibody responses, as compared with only 1 of 24 subjects without clinical evidence of vaccinia virus replication. Vigorous cytotoxic T-cell and interferon-γ responses occurred in 94 percent of subjects with vesicles, and a cytotoxic T-cell response occurred in only one subject without a vesicle. Conclusions: The vaccinia virus vaccine (which was produced in 1982 or earlier) still has substantial potency when administered by a bifurcated needle to previously unvaccinated adults. Diluting the vaccine reduces the rate of successful vaccination. The development of vesicular skin lesions after vaccination correlates with the induction of the antibody and T-cell responses that are considered essential for clearing vaccinia virus infections. (N Engl J Med 2002;346:1275-80.) [ABSTRACT FROM AUTHOR]

Background. Vaccinia virus (VV) membrane proteins are candidates for orthopoxvirus subunit vaccines and potential targets for therapeutic antibodies. Human antibody responses to these proteins after VV vaccination have not been well characterized. Methods. Pre- and postvaccination (day 26-30) serum specimens from 80 VV vaccine recipients were examined for immunoglobulin G antibodies specific for B5, A33, A27, and L1 by enzyme-linked immunosorbent assay (ELISA). Responses were compared between vaccinia-naive and previously vaccinated (nonnaive) recipients and between nonnaive recipients of undiluted or 1:10 diluted vaccine. Results. VV vaccination elicited anti-A33 and anti-A27 antibodies in nearly all vaccinia-naive subjects (100% and 93%, respectively). Preexisting antibodies were commonly detected in nonnaive subjects (for anti-B5, 68%; for anti-A33, 59%; for anti-A27, 38%; and for anti-L1, 10%). Anti-B5 antibodies were strongly boosted by undiluted vaccine (geometric mean titer [GMT], 151 vs. 1010 for pre- vs. postvaccination; ), whereas anti-L1 antibody P ! .001 responses were less robust (detection rate, 31%; GMT, 75) in nonnaive subjects. Diluted vaccine elicited antibody responses that were similar to those elicited by undiluted vaccine. Conclusions. Vaccination with VV elicits long-lived specific antibody responses directed against VV membrane proteins that vary by previous vaccination status but not with respect to 10-fold dilution of vaccine. B5, A33, and A27 should be considered for inclusion in future human orthopoxvirus subunit vaccines. [ABSTRACT FROM AUTHOR]

We developed a carboxyfluorescein succinimidyl ester (CFSE)-based flow-cytometric assay that can detect different subsets of vaccinia-specific T cells capable of both antigen-specific expansion and protective effector functions. Proliferation and effector functions were detected by CFSE dilution and intracellular staining, respectively. Absolute numbers of CD4+/CFSElo/interferon (IFN)-γ+, CD8+/CFSElo/IFN-γ+,CD8+/CFSElo/granzyme A+, and CD8+/CFSElo /CD107a+ T cells present after in vitro stimulation with live vaccinia were significantly higher in immunized individuals (P< .05). These CD4+ and CD8+ T cell increases were >2 log higher than increases detectable by standard lymphoproliferation and cytotoxicity assays. Vaccinia-specific CD8+/CFSEloIFN-γ+ and granzyme A+ T cell responses were significantly correlated with the results of standard 51Cr-release cytolytic assays (P< .05). Furthermore, vaccinia induced antigen-specific memory γδ T cells. We demonstrate that vaccinia induces robust memory effector CD4+, CD8+, and γδ T cells, all of which are relevant for protection against smallpox. CFSE-based flow-cytometric assays will be useful in evaluating cell-mediated immune responses induced by new smallpox vaccines. [ABSTRACT FROM AUTHOR]

Background. Chronically ill older adults constitute a population vulnerable for complications associated with influenza. Study of their immunity to influenza virus may help design better strategies to stimulate protective immune responses. Methods. Immunogenicity of influenza vaccines and immune protection from natural influenza were assessed in older adults with chronic obstructive pulmonary disease as part of a vaccine efficacy trial. Subjects received either trivalent inactivated influenza virus vaccine (TVV) intramuscularly and trivalent live cold-adapted influenza virus vaccine (CAIV-T; n = 1107) intranasally (inl) or TVV and placebo inl (P; n = 1108). Results. In the subsets of study subjects assessed, serum hemagglutination inhibition (HAI) and nasal-wash antihemagglutinin (HA) immunoglobulin (Ig) A and IgG antibody levels and anti-influenza virus CD8+ cytotoxic T lymphocyte activity increased after immunization. Mean postimmunization nasal-wash IgA antibody levels to influenza A H3/HA and B HA were statistically higher in the group (n = 957 ) than in the TVV+CAIV-T group ( n = 951). Postimmunization serum HAI and nasal-wash IgA antibodies to influenza A/H3N2 TVV+P and B viruses were associated with a reduced relative risk for natural influenza infection. Conclusions. appeared more immunogenic than , but the observed difference may TVV+CAIV-T TVV+P be clinically unimportant. Anti-influenza serum and nasal-wash antibodies were associated with immuneprotection. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article titled "Interferon-Mediated Antiviral Immunity Against Orthopoxvirus Infection Is Provided by T cells," by C. Agrati, C. Castiletti and R. De Santis, published in a 2006 issue of the "Journal of Infectious Diseases."

Presents a research letter to the editor on the immune status in a primary smallpox vaccinee who failed to develop an immunization site reaction.

Highlights: [•] Reintroduction of Variola major as an agent of bioterrorism remains a concern. [•] A compressed schedule of MVA was evaluated for use in a post event scenario. [•] MVA is well tolerated when given as two standard doses at Days 0 and 28 or 0 and 7. [•] A 2nd dose of MVA at Day 28 compared to Day 7 provided greater antibody responses. [•] INF-γ expression was greatest within 2 weeks after last vaccination. [ABSTRACT FROM AUTHOR]

Immunization with vaccinia virus elicits a protective Ab response that is almost completely CD4+ T cell dependent. A recent study in a rodent model observed a deterministic linkage between Ab and CD4+ T cell responses to particular vaccinia virus proteins suggesting that CD4+ T cell help is preferentially provided to B cells with the same protein specificity (Sette et al. 2008. Immunity 28: 847-858). However, a causal linkage between Ab and CD4+ T cell responses to vaccinia or any other large pathogen in humans has yet to be done. In this study, we measured the Ab and CD4+ T cell responses against four vaccinia viral proteins (A27L, A33R, B5R, and L1R) known to be strongly targeted by humoral and cellular responses induced by vaccinia virus vaccination in 90 recently vaccinated and 7 long-term vaccinia-immunized human donors. Our data indicate that there is no direct linkage between Ab and CD4+ T cell responses against each individual protein in both short-term and long-term immunized donors. Together with the observation that the presence of immune responses to these four proteins is linked together within donors, our data suggest that in vaccinia-immunized humans, individual viral proteins are not the primary recognition unit of CD4+ T cell help for B cells. Therefore, we have for the first time, to our knowledge, shown evidence that CD4+ T cells provide intermolecular (also known as noncognate or heterotypic) help to generate robust Ab responses against four vaccinia viral proteins in humans. [ABSTRACT FROM AUTHOR]

Modified vaccinia virus Ankara (MVA) is a highly attenuated vaccinia virus that is under consideration as an alternative to the conventional smallpox vaccine Dryvax. MVA was attenuated by extensive passage of vaccinia virus Ankara in chicken embryo fibroblasts. Several immunomodulatory genes and genes that influence host range are deleted or mutated, and replication is aborted in the late stage of infection in most nonavian cells. The effect of these mutations on immunogenicity is not well understood. Since the structural genes appear to be intact in MVA, it is hypothesized that critical targets for antibody neutralization have been retained. To test this, we probed microarrays of the Western Reserve (WR) proteome with sera from humans and macaques after MVA and Dryvax vaccination. As most protein sequences of MVA are 97 to 99% identical to those of other vaccinia virus strains, extensive binding cross-reactivity is expected, except for those deleted or truncated. Despite different hosts and immunization regimens, the MVA and Dryvax antibody profiles were broadly similar, with antibodies against membrane and core proteins being the best conserved. The responses to nonstructural proteins were less well conserved, although these are not expected to influence virus neutralization. The broadest antibody response was obtained for hyperimmune rabbits with WR, which is pathogenic in rabbits. These data indicate that, despite the mutations and deletions in MVA, its overall immunogenicity is broadly comparable to that of Dryvax, particularly at the level of antibodies to membrane proteins. The work supports other information suggesting that MVA may be a useful alternative to Dryvax. [ABSTRACT FROM AUTHOR]

Background. Innate immunity, including Toll-like receptor (TLR)-mediated expression of the B7 costimulatory molecules CD80 and CD86, is critical for vaccine immunity. We examined whether CD80 and CD86 expression vary with aging and predict response to the trivalent inactivated influenza vaccine. Methods. One hundred sixty-two subjects between 21 and 30 years of age (the young group) or ⩾65 years of age (the older group) enrolled before vaccination. We determined TLR-induced monocyte CD80/CD86 expression by flow cytometry and vaccine antibody responses by hemagglutination inhibition. Results. The mean increase in TLR-induced CD80+ monocytes was reduced in older, compared with young, adults by 68% (P = .0002), and each decile increase of CD80+ cells was associated with an 8.5% increase in mean number of vaccine strains with a ⩾4-fold titer increase (P = .01) and a 3.8% increase in mean number of strains with a postvaccine titer ⩾1:64 (P = .037). Each decile decrease of CD86+ cells was associated with an 11% increase in the mean number of strains with a 4-fold increase (P = .002) and a 3.9% increase in the mean number of strains with a postvaccine titer ⩾1:64 (P = .07). Conclusions. CD80 and CD86 expression on activated monocytes is highly associated with influenza vaccine response. This approach prospectively identifies adults unlikely to respond to immunization who may benefit from alternative vaccines or antiviral prophylaxis during influenza outbreaks. [ABSTRACT FROM AUTHOR]

Background. When the decision was made to prepare for a deliberate release of smallpox, the United States had ~15 million doses of Wyeth Dryvax vaccine, which was known to induce significant morbidity when used undiluted; Sanofi Pasteur, Inc., later identified ~85 million additional doses in storage. Methods. Eleven vaccine-dose groups, each with 30 vaccinia-naive subjects, were given diluted Dryvax vaccine or 1 of 2 lots of Sanofi Pasteur smallpox vaccine and were evaluated for vaccination success rates, morbidity, and immune responses. Results. Estimated doses of 106.6-108.2 pfu of virus/mL induced major reactions (or ‘takes’) in 93%-100% of subjects in each dose group. No differences in vaccination take rates, lesion size, erythema, and induration or in serum neutralizing-antibody response were detected between the groups. However, systemic reactogenicity and missed activities were significantly lower for the vaccine groups given doses of 106.6-107.2 pfu/mL than for those given doses of 107.6-108.2 pfu/mL. Conclusions. These findings support the use of a higher dilution of Wyeth Dryvax vaccine and Sanofi Pasteur smallpox vaccine, given that the resulting morbidity should be significantly lower without loss of vaccine effectiveness. A plan for use of higher dilutions would create an enormous stockpile of vaccine. [ABSTRACT FROM AUTHOR]

Background. Postexposure vaccination strategies rely on a rapid induction of poxvirus-specific immune responses. Postvaccination cell-mediated immune (CMI) responses have not been compared by use of controlled trials in previously vaccinated (vaccinia-nonnaive) and nonvaccinated (vaccinia-naive) individuals. Methods. To assess the time course of vaccinia-specific CMI responses, 20 previously vaccinated and 10 vaccinia-naive individuals were vaccinated with Dryvax, and serial blood samples were drawn. Results. Both groups developed peak levels of vaccinia-specific interferon (IFN)-γ-producing T cells by day 14 after vaccination. In vaccinia-nonnaive individuals, vaccinia-specific CMI responses were detected by day 7 after vaccination and preceded the increase in antibody titers. IFN-γ enzyme-linked immunospot responses were significantly different between the 2 groups on days 7 (greater in vaccinia-nonnaive than in vaccinia-naive individuals) and 14 (greater in vaccinia-naive than in vaccinia-nonnaive individuals). Lymphoproliferation responses in vaccinia-nonnaive individuals were significantly higher on days 3 and 7, but cytotoxic T cell lysis activity was not statistically different at any time point. Antibody responses conformed to expected primary and secondary patterns of induction. Conclusions. This study demonstrates that the kinetics of CMI responses are different after primary vaccination versus after revaccination and indicates that memory can exist in individuals vaccinated &ges;30 years ago. These data support the epidemiological observation in smallpox outbreaks that successful revaccination within 4 days of exposure is partially protective. In vaccinia-nonnaive individuals, protection against smallpox during the post- exposure revaccination period may require T cell memory as an essential component for the rapid induction of protective cellular and humoral responses. [ABSTRACT FROM AUTHOR]

Background: To evaluate the potential to increase the supply of smallpox vaccine (vaccinia virus), we compared the response to vaccination with 108.1, 107.2, and 107.0 plaque-forming units (pfu) of vaccinia virus per milliliter. Methods: In this randomized, single-blind, prospective study, 680 adults who had not been previously immunized were inoculated intradermally with undiluted vaccine (mean titer, 108.1 pfu per milliliter), a 1:5 dilution, or a 1:10 dilution of vaccinia virus with use of a bifurcated needle, and the site was covered with a semipermeable dressing. Subjects were monitored for vesicle formation (an indicator of the success of vaccination) and adverse events for 56 days after immunization. Results: Success rates did not differ significantly among the groups and ranged from 97.1 to 99.1 percent after the first vaccination. Both the undiluted and diluted vaccines were reactogenic. In addition to the formation of pustules, common adverse events included the formation of satellite lesions, regional lymphadenopathy, fever, headache, nausea, muscle aches, fatigue, and chills consistent with the presence of an acute viral illness. Generalized and localized rashes, including two cases of erythema multiforme, were also observed. Conclusions: When given by a bifurcated needle, vaccinia virus vaccine can be diluted to a titer as low as 107.0 pfu per milliliter (approximately 10,000 pfu per dose) and induce local viral replication and vesicle formation in more than 97 percent of persons. (N Engl J Med 2002;346:1265-74.) [ABSTRACT FROM AUTHOR]