Inmunizaciones en niños, adolescentes y adultos inmunosuprimidos / Immunizations in children, adolescent and adult immunocompromised hosts

Los pacientes inmunosuprimidos presentan un riesgo mayor de infecciones, debido a sus disfunciones inmunes, producto de la actividad de su enfermedad y la terapia inmunosupresora. El uso de vacunas disminuye este riesgo, otorgando protección directa e indirecta, a través de la vacunación del paciente y sus contactos. Las vacunas inactivadas han demostrado un perfil de seguridad adecuado en estos pacientes, por lo que no están contraindicadas, aunque su respuesta inmune puede ser inadecuada. Las vacunas vivas atenuadas, formalmente contraindicadas, poseen una información creciente que permite evaluar su riesgo/beneficio de manera individual. Por este motivo es necesario procurar mantener el calendario de vacunas actualizado y complementado, evitando el retraso en esquemas de vacunación y poniéndolo al día lo antes posible, con estrategias basadas en el individuo. Para llevar a cabo esto, se debe conocer y considerar los intervalos entre las vacunas, los esquemas acelerados, la solicitud de vacunas especiales, las aprobaciones vigentes y, finalmente, sus contraindicaciones.

Immunecompromised patients are at higher risk of infections due to their immune dysfunction caused by ongoing disease processes and immunosuppressive therapy. Patient vaccination or vaccination of the people in contact with patients diminishes their risk of infection. Although the immune response of immunocompromised patients might be impaired, the use of inactivated vaccines is safe and it is not contraindicated in these patients. Formerly, live attenuated vaccines were contraindicated in immunecompromised patients, but recently more data supports their use when evaluating case by case the risks and benefits of their application. Thus, it is important to keep and up-to-date, taylor-based and enhanced vaccination schedule in these cases. For this, specialists need to be informed about the availability of regular and special vaccines, their current approvals, vaccine administration protocols under specific situations and vaccine contraindications.

Immunogenicity and Safety of Trivalent Inactivated Influenza Vaccine: A Randomized, Double-Blind, Multi-Center, Phase 3 Clinical Trial in a Vaccine-Limited Country

Influenza vaccines are the primary method for controlling influenza and its complications. This study was conducted as a phase 3, randomized, double-blind, controlled, multi-center trial at seven university hospitals to evaluate the immunogenicity and safety of an inactivated, split, trivalent influenza vaccine (GC501, Green Cross Corporation, Yongin, Korea), which was newly manufactured in Korea in 2008. Between September 21 and 26, a total of 329 healthy subjects were recruited for the immunogenicity analysis, while 976 subjects were enrolled for the safety analysis. The GC501 vaccine met both FDA and EMEA criteria with > or = 80% of subjects achieving post-vaccination titers > or = 40 for all three subtypes, even in the elderly. The vaccine was well tolerated with only mild systemic and local adverse events. In summary, GC501 showed excellent immunogenicity and a good safety profile in both young adults and the elderly. The licensure of GC501 might be an important basis in preparation for the future influenza pandemic.

Protection of chicken against very virulent IBDV provided by in ovo priming with DNA vaccine and boosting with killed vaccine and the adjuvant effects of plasmid-encoded chicken interleukin-2 and interferon-gamma

The aim of this study was to examine the efficacy of in ovo prime-boost vaccination against infectious bursal disease virus (IBDV) using a DNA vaccine to prime in ovo followed by a killed-vaccine boost post hatching. In addition, the adjuvant effects of plasmid-encoded chicken interleukin-2 and chicken interferon-gamma were tested in conjunction with the vaccine. A plasmid DNA vaccine (pcDNA-VP243) encoding the VP2, VP4, and VP3 proteins of the very virulent IBDV (vvIBDV) SH/92 strain was injected into the amniotic sac alone or in combination with a plasmid encoding chicken IL-2 (ChIL-2) or chicken IFN-gamma (ChIFN-gamma) at embryonation day 18, followed by an intramuscular injection of a commercial killed IBD vaccine at 1 week of age. The chickens were orally challenged with the vvIBDV SH/92 strain at 3 weeks of age and observed for 10 days. In ovo DNA immunization followed by a killed-vaccine boost provided significantly better immunity than the other options. No mortality was observed in this group after a challenge with the vvIBDV. The prime-boost strategy was moderately effective against bursal damage, which was measured by the bursa weight/body weight ratio, the presence of IBDV RNA, and the bursal lesion score. In ovo DNA vaccination with no boost did not provide sufficient immunity, and the addition of ChIL-2 or ChIFN-gamma did not enhance protective immunity. In the ConA-induced lymphocyte proliferation assay of peripheral blood lymphocyte collected 10 days post-challenge, there was greater proliferation responses in the DNA vaccine plus boost and DNA vaccine with ChIL-2 plus boost groups compared to the other groups. These findings suggest that priming with DNA vaccine and boosting with killed vaccine is an effective strategy for protecting chickens against vvIBDV.

Protective efficacy of commercial inactivated Newcastle disease virus vaccines in chickens against a recent Korean epizootic strain

Despite the intensive vaccination policy that has been put in place to control Newcastle disease virus (NDV), the recent emergence of NDV genotype VII strains in Korea has led to significant economic losses in the poultry industry. We ssessed the ability of inactivated, oil-emulsion vaccines derived from La Sota or Ulster 2C NDV strains to protect chickens from challenge with Kr-005/00, which is a recently isolated Korean epizootic genotype VII strain. Six-week-old SPF chickens were vaccinated once and challenged three weeks later via the eye drop/intranasal route. All vaccinated birds were fully protected from disease, regardless of the vaccine strains used. All vaccinated and challenged groups showed significant sero-conversion 14 days after challenge. However, some vaccinated birds, despite being protected from disease, shed the challenge virus from their oro-pharynx and cloaca, albeit at significantly lower titers than the unvaccinated challenged control birds. The virological, serological, and epidemiological significance of our observations with regard to NDV disease eradication is discussed.

La prevención de la influenza: recomendaciones para la temporada de 2005-2006 / Preventing influenza: recommendations for the 2005-2006 season

Influenza is a serious health problem worldwide due to the epidemics and pandemics that it periodically causes. The Advisory Committee on Immunization Practices (ACIP) of the United States of America recently published updated recommendations for influenza prevention and control for the 2005-2006 season. Many of these guidelines are of interest to the countries of the Region of the Americas, particularly those related to vaccination, which is the mainstay for preventing and controlling this disease. Various changes have been made in the recommendations that were published in 2004. First, the ACIP recommends vaccination against influenza for persons with any condition (e.g., cognitive dysfunction, spinal cord injury, seizure disorder, or other neuromuscular disorder) that can compromise respiratory function or make eliminating respiratory secretions difficult or that can increase the risk for aspiration. Second, the ACIP strongly recommends that all health care workers be vaccinated against influenza annually and encourages facilities that employ health care workers to vaccinate them by using approaches that maximize immunization rates. Third, the ACIP encourages the use of both available vaccines (inactivated and live, attenuated influenza vaccine (LAIV)) for eligible persons every influenza season, especially persons in recommended target groups. When inactivated virus vaccine is in short supply, the use of LAIV is especially encouraged, if feasible, for eligible persons (including health care workers) because such use might considerably increase the availability of inactivated virus vaccine for persons in high-risk groups. Fourth, the 2005-06 trivalent vaccine virus strains are A/California/7/2004 (H3N2)-like, A/New Caledonia/20/99 (H1N1)-like, and B/Shanghai/361/2002-like antigens. For the A/California/7/2004 (H3N2)-like antigen, manufacturers may use the antigenically equivalent A/ New York/55/2004 virus, and for the B/Shanghai/361/2002-like antigen, manufacturers may use the antigenically equivalent B/Jilin/20/2003 virus or B/Jiangsu/10/2003 virus.

Coverage and costs of mass immunization of an oral cholera vaccine in Vietnam.

The objective of this study was to describe a mass-immunization campaign of a locally-produced oral, killed whole-cell cholera vaccine in Hue city, Vietnam. Mass immunization with a 2-dose regimen of the vaccine was conducted in 13 communes in early 1998. The total, age- and sex-specific vaccine coverage was calculated using data from the vaccination records and the government census. The number of vaccine doses procured, administered, wasted, and left over, and the human and other resources required to prepare and conduct the vaccination campaign were systematically recorded. Government expenditure for planning, procurement, and delivery of the vaccine were documented. In total, 118,555 (79%) of the 49,557 targeted population were fully vaccinated during the mass-vaccination campaign. The total expenditure for the project was US dollar 105,447, resulting in a cost per fully-vaccinated person of US dollar 0.89. Mass immunization with this locally-produced oral, killed cholera vaccine was found to be feasible and affordable with attainment of high vaccination coverage.

Comparison of the reactogenicity and immunogenicity of two different dose levels of hepatitis A vaccine in healthy children and adolescents.

An open study was performed to compare the reactogenicity and immunogenicity of an inactivated hepatitis A vaccine administered in two different doses and schedules to 460 healthy volunteers aged 3-18 years. Participants were randomized to two groups to receive either two doses of 720 ELISA Units (EL.U) inactivated hepatitis A per 0.5 ml dose according to a 0, 6-month schedule, or three doses of 360 EL.U according to a 0, 1, 6-month schedule. Transient local injection soreness was the most commonly reported symptom in almost half of both groups with no serious adverse events. One month after the primary course (one dose of 720 EL.U and two doses of 360 EL.U), 99% of 720 EL.U vaccinees had seroconverted, compared with 100% seroconversion in the 360 EL.U group. All vaccinees were seropositive after the booster dose of both vaccines with geometric mean anti-HAV titers of 2,359 and 2,967 mIU/ml in the 720 EL.U and 360 EL.U groups, respectively. The vaccine containing 720 EL.U of antigen per dose offers the advantage of convenience and acceptance of immunization afforded by a two-dose course of vaccination accompanied by a comparable antibody response with that achieved after three doses of vaccine containing 360 EL.U of antigen per dose.

Dos vacunas antipoliomielíticas: ventajas y desventajas / Two antipoliomyelitis vaccines: advantages and disadvantages

La vacuna oral antipoliomielítica elaborada con virus vivos atenuados es actualmente la de elección en México. En 1978 van Wezel incrementó la antigenicidad de la vacuna elaborada con virus inactivados por rayos ultravioleta, a la cual se denominó vacuna de potencia incrementada (elPV, enhanced inactivated polio vaccine). Existe clara evidencia en países europeos de que también con esta última se obtiene una protección adecuada, lo que ha permitido considerarla como una alternativa en los esquemas de inmunización. Se describen las dos vacunas, oral y elPV, los esquemas de inmunización que actualmente se proponen y sus ventajas y desventajas

Administration of non activated infectious bursal disease oil-emulsion vaccine to commercial layer chickens at different ages

Commercial layer chickens of different ages carrying maternal antibody levels to infectious bursal disease [IBD] were inoculated with a full dose a commercial inactivated oil-emulsion IBD vaccine, and then challenged with very virulent IBD virus [vvIBDV] at 7 and 14 days post-vaccination [PV]. The results revealed complete absence of vaccinal protection [0%] one week PV and poor vaccinal protection [10- 50%] two weeks PV, when vaccination adopted weekly during the period from 7 up to 35 days of age. However, survivors during this period showed bursal lesions and significant [P <0.05] bursal atrophy two weeks PV despite vaccinal protection conferred against mortality

Trial of non-living crude vaccine against zoonotic cutaneous leishmaniasis

A field trial was carried out on 60 volunteers selected in Yazd province, central Iran, with a vaccine containing killed promastigotes of L. major prepared by the Razi Institute, Hessarak. During these phase I studies which lasted for more than two years, we examined acceptable doses of the vaccine alone or mixed with BCG. The results so far indicate that 50 to 1000 micro g of the vaccine alone can be well tolerated without major side-effects. The mixture of BCG with 400 micro g of the vaccine produced pain and itching in five out of six volunteers, a self-limiting lymphadenopathy in one out of six, and fever in three out of six. Further trials are planned with reduced doses of BCG. The leishmania skin test became positive in a high proportion of the treated individuals after vaccination. Circulating antibodies were detected from two weeks to one month after vaccination

Field evaluation of formalin inactivated Kyasanur forest disease virus tissue culture vaccine in three districts of Karnataka state.

A formalin inactivated Kyasanur forest disease (KFD) virus tissue culture vaccine produced by the health department of the State Government of Karnataka at Shimoga was administered in Shimoga, Uttar Kannada and Chikmangalur districts during 1990-92 KFD epidemic seasons. The selection of places for vaccination was based on the prevalence of KFD activity in previous years; villages adjacent to KFD affected areas and the villages from which mortality in monkeys was reported. A total of 284 villages was covered under vaccination; 26850 individuals received one dose whereas, 61302 received two doses of vaccine. No untoward reaction was observed in any of the vaccinees. In the 72 KFD affected villages there were 14 patients among 9072 and 10 among 21083 vaccinees receiving one and two doses respectively, whereas 325 patients were reported among 37373 unvaccinated individuals during the same period. In 1990-91 the number of males patients was more than females whereas, in 1991-92 the ratio was reserved. On analysis indicated that the vaccine has a highly significant protective effect.

Immunogenicity of low dose Japanese encephalitis vaccine (BIKEN) administered by the intradermal route: preliminary data.

Two hundred twenty-four immune and non-immune adults were systematically assigned to receive a single dose of Nakayama strain JEVAC in one of four study "arms": 0.1 ml ID, 0.2 ml ID (injection of 0.1 ml at two sites), 0.3 ml ID (injection of 0.1 ml at three sites), or 1.0 ml SC. Immune responses after this single dose (in many cases "booster") was assumed to reflect immune responses of a primary series and was assessed qualitatively (percent seroconvertion) and quantitatively (geometric mean titer) a 30 and 90 days post immunization. The results showed that JEVAC given 0.1 ml. ID at two sites is likely to be as immunogenic as 1.0 ml. given SC.

Reduction in the dosage schedule of BPL-inactivated neural tissue vaccine for rabies prophylaxis in man.

There exist two different immunization schedules for neural tissue rabies vaccine (NTV) for human use in India, the amount of vaccine given by the schedule recommended by Central Research Institute (CRI), Kasauli, being higher than that recommended by Pasteur Institute of India (PII), Coonoor. A study was therefore undertaken to assess the feasibility of reducing the CRI dosage schedule for rabies prophylaxis. The antirabies antibody response in laboratory animals and human subjects following 7, 10 and 14 daily doses of NTV with or without administering rabies immune globulin (RIG) was much higher than the minimum protective level of 0.5 IU/ml of serum. Based on these results, the CRI schedule could be reduced from 14 x 5 ml of NTV to 10 x 5 ml in class II and class III rabies exposure cases.

Immune responses following killed whole vibrio-B subunit oral cholera vaccine in human volunteers.

Immunogenicity of killed whole vibrio and B subunit oral cholera vaccines in American and Thai volunteers were analysed in terms of significant rise of antibody titre. Three doses of 2 x 10(11) killed vibrios and 5 mg of cholera toxin B subunit were given at two-week intervals. There were no differences in the percent of volunteers with significant rise of serum immunoglobulin G and secretory immunoglobulin A (sIgA) to cholera toxin. However, the percent with significant rises of serum antibody to whole cell V. cholerae Inaba measured by vibriocidal titre and serum immunoglobulin G, and secretory immunoglobulin A to lipopolysaccharide (LPS) measured by ELISA in American volunteers were significantly different from those in Thai volunteers (89% VS 45%, 68% VS 9% and 53% VS 0%, respectively) (p less than 0.05).

Evaluation of the efficacy of candidate vaccines against M. leprae infection in mice.

Delayed-typed hypersensitivity (DTH) response and protection value of some of the candidate vaccines alone and in combination with BCG has been investigated. It was observed that both M.w. and BCG gave heightened DTH and good protection. On the other hand both M. leprae and ICRC evoked moderate DTH and gave poor protection. However on combining any of these candidate vaccines with live BCG, the lowering of DTH and poor protection was observed except in the M. leprae combination which in spite of low DTH gave better protection.