Vaccine reports最新文献

Efficacy of the Leptospira components of EURICAN¹ DAPPi-Lmulti, a canine combined vaccine, was tested after a primary course of two subcutaneous injections of one dose given 4 weeks apart to puppies aged from seven to nine weeks. Challenges with three pathogenic serovars of Leptospira spp. (Canicola, Icterohaemorrhagiae and Grippotyphosa) were carried out 14 days (onset of immunity studies – OOIs) and 13–15 months (duration of immunity studies – DOIs) after primary vaccination. During the four-week post challenge monitoring period, daily clinical observations were recorded, and blood (culture, biochemistry and haematology), urine (culture) and kidney (culture and histology) samples were collected regularly throughout the study or at necropsy. In OOIs, vaccination prevented mortality, clinical signs of the disease, infection, urinary excretion, renal carriage and renal lesions for all serovars. In DOIs, mortality, clinical signs and infection were less frequent in controls challenged with serovars Canicola and Grippotyphosa than in OOIs whereas they were absent or mild and transient in vaccinated dogs. Urinary excretion, renal carriage and renal lesions were at least significantly reduced in vaccinated dogs compared to controls for all serovars.

These studies demonstrated that the tested vaccine provides a quick onset of immunity as early as two weeks post-vaccination and a long-term immunity of 13–15 months with full protection against fatal leptospirosis for serovar Icterohaemorrhagiae; prevention of mortality and clinical signs, and reduction of infection, urinary excretion, renal carriage and renal lesions for serovar Canicola; and prevention of mortality and reduction of clinical signs, infection, urinary excretion, renal carriage and renal lesions for serovar Grippotyphosa.

Streptococcus pneumoniae is a leading cause of pneumonia, the most common cause of childhood death. Papua New Guinean children experience high rates of nasopharyngeal pneumococcal colonization within weeks of birth, predisposing them to pneumococcal disease. In a trial to determine the safety and immunogenicity of early infant vaccination with 7-valent pneumococcal conjugate vaccine (7vPCV), we investigated the impact of early schedules on pneumococcal carriage.

Infants were randomized at birth to receive 7vPCV in a 0–1–2-month (n = 101) or a 1–2–3-month (n = 105) schedule or no 7vPCV (n = 106). All children received 23-valent pneumococcal polysaccharide vaccine at age 9 months. We cultured nasopharyngeal swabs (NPS) collected at ages 1, 2, 3, 4 weeks and 3, 9, 18 months, and middle ear discharge if present. Pneumococcal serotypes were identified by the Quellung reaction.

A total of 1761 NPS were cultured. The prevalence of pneumococcal carriage was 22% at 1 week of age, rising to 80% by age 3 months and remained >70% thereafter, with high-density carriage in 42% of pneumococcus-positive samples. We identified 63 different serotypes; 43% of isolates from controls were 13vPCV serotypes. There were no significant differences in 7vPCV serotype carriage between 7vPCV recipients and controls at any age (22% vs. 31% at 9 months, p = 0.2). At age 9 months the prevalence of non-7vPCV carriage was 17% higher in 7vPCV recipients (48%) than in controls (25%, p = 0.02). More non-7vPCV serotypes were isolated from ear discharge in 16 7vPCV recipients than from 4 controls (48% vs. 25%, p = 0.13).

The limited impact of neonatal or accelerated infant 7vPCV schedules on vaccine serotype carriage is probably due to the early onset of dense carriage of a broad range of pneumococcal serotypes. While serotype-independent pneumococcal vaccines are needed in high-risk populations, the underlying environmental factors and sources of infection must be investigated.

http://clinicaltrials.gov/ct2/show/NCT00219401.

The great genetic and antigenic diversity of PRRSV, an RNA virus that causes PRRS, makes the control of this disease very difficult. To achieve broad protection to infection with this divergent virus, two T-cell mosaic sequences were designed based on 748 glycoprotein 5 (GP5) sequences using the Mosaic T-Cell Vaccine Tool Suite from the Los Alamos National Laboratory. Two DNA vaccines were constructed using the mosaic sequences thus designed. The amino acid sequences of the GP5-Mosaic vaccines were closer to strains that differ from VR2332 by at least 10%. Expression of the GP5-Mosaic vaccines was verified in E. coli BL21 (DE3) by western blot. The immunogenicity of the GP5-Mosaic vaccines was tested by vaccinating young pigs with either a gene gun (Trial 1) or by electroporation (Trial 2) followed by challenge with VR2332. Lymphocyte proliferative responses detected in virus-stimulated peripheral blood mononuclear cells (PBMC) of GP5-Mosaic-vaccinated pigs were higher than those of control pigs in both trials. In Trial 2, significantly higher levels of IFN-γ mRNA expression and lower levels of IL-10 mRNA were detected in virus-stimulated PBMC of GP5-Mosaic-vaccinated pigs as compared to control pigs. In ELISA, higher virus-specific antibodies were detected in sera from GP5-Mosaic-vaccinated animals than those detected in control animals. These antibodies were proven to be neutralizing. The viral copy numbers in serum 5 days after challenge with VR2332 decreased over 260-fold within 2 days in GP5-Mosaic-vaccinated pigs, while the viral copy numbers increased by 1.2 to 5-fold in control animals in the same period. Additionally, the viral loads in inguinal lymph nodes and spleen, and lung lesions scores of GP5-Mosaic-vaccinated animals were lower compared to those of control animals. Together the data led us to conclude that the GP5-Mosaic vaccine was immunogenic and induced partial protection in vaccinated pigs.

Though rare, neurological serious adverse events following measles immunization are well documented in scientific literature. However, we could retrieve only 7 published reports of optic neuritis following measles/measles containing vaccines. We report a case of bilateral optic neuritis that developed within 24 h of administration of monovalent measles vaccine in an eight-year-old male child during special measles immunization campaign in India.

Introduction

A cluster vaccination coverage survey was conducted in two districts, Dowa and Ntchisi, in Malawi to measure the vaccination coverage of children 12–23 months old and identify factors impacting the utilization of vaccination service.

Methods

A cross-sectional descriptive cluster survey with 30 clusters and 10 children per cluster was administered in each district including a total of 601 children surveyed. 57 village heads and 60 health surveillance assistants (HSAs) were also interviewed.

Findings

The vaccination card availability was very high in both districts (94%). Vaccination coverage by card plus history of mothers was very high, above 93% for all antigens, and the coverage by card alone was also high with a range of pentavalent₁ coverage of 91% in Ntchisi and 83% in Dowa to measles coverage of 81% and 83% in Dowa and Ntchisi respectively. However, the percentage of valid doses administered to fully immunized children was low (60% in Dowa and 49% in Ntchisi). About 10% of the pentavalent₁ doses in Dowa and 9% in Ntchisi were administered before six weeks of age and 7% and 8% of the pentavalent₃ doses in Dowa and Ntchisi districts respectively were administered in less than 28 days after pentavalent₂. Similarly, 15% of measles doses in both Dowa and Ntchisi districts were administered before 270 days. The main reason for no vaccination was vaccine stock outs at health facility level. The majority of village heads are satisfied with the vaccination service in their communities. Health surveillance assistants (HSAs), village heads and religious leaders all play major roles in mobilization for vaccination service in the two districts.

Conclusion

Dowa and Ntchisi districts have high vaccination coverage, however many children receive invalid doses. This finding calls for immediate action to educate the service providers on administration of valid doses.

Epitope mapping has emerged as a powerful tool to design vaccines. It proved itself a number of times to reveal the building blocks of potent immuno-prophylactics. T-cell epitope mapping aims to identify the shortest amino acid sequence of an epitope of a specific antigen that is recognized by CD4+ and/or CD8+ T-cells. T-cell epitopes have the potential to stimulate both long lasting and exclusive cytotoxic immune response. Therefore, they are crucial for vaccine development against emerging intracellular pathogens such as Plasmodium malaria, Mycobacterium spp., genital Chlamydia, HIV, HCV as well as cancer cells. This review documents and discusses the different methods used in T-cell epitope mapping, and the role of each method to identify the potent epitopes in viruses, bacteria, parasites, as well as human diseases. The comment of the article guides the researchers to identify the most suitable mapping techniques for their antigens.

A mass vaccination campaign with the 4CMenB vaccine (Bexsero®) was launched in a serogroup B endemic area in Quebec. A study was conducted to assess parents’ and adolescents’ opinions about the acceptability of the vaccine before and after the campaign (two telephone surveys). This paper reports the results of the second survey and describes the factors associated with complete and incomplete 4CMenB vaccine status. Overall, 82.5% of children and 58.7% of adolescents were completely vaccinated. A positive association between intention reported prior to the campaign and vaccine receipt reported after the campaign was observed for both children and adolescents. Protection against meningococcal diseases was the main reason reported for those who completed the 4CMenB dose series, while lack of time, interest or information remained one of the main reasons for having refused the vaccine or not having completed the series. About half of the vaccinees reported an adverse event after having received a dose of 4CMenB and pain at the injection site and fever were the most often cited. Neither negative perceptions regarding the safety of the vaccine nor report of adverse events after having received a dose of the vaccine were associated with the vaccine refusal.

Introduction

We investigated the extent to which school-specific kindergarten vaccination up-to-date status prevalence differs by public and private school types, student demographic composition, and geographic location across schools in Vancouver, and four adjacent British Columbia communities, during 2013–14.

Methods

School-specific kindergarten coverage for seven vaccinations plus up-to-date status were merged with data on school type and student sociodemographic composition for 219 schools within 9 Local Health Areas (LHAs).

Results

In adjusted Tobit regression models, private non-religious (versus public) schools were associated with lower up-to-date status (b = −9.51 percentage points). Student enrollment was positively associated with higher coverage, while greater number of English Language Learners (ELL), students speaking English at home, and Aboriginal students were each negatively associated with up-to-date coverage. The most socioeconomically disadvantaged and advantaged LHAs had the lowest coverage.

Conclusion

Our findings identify lower coverage among some types of private schools and in affluent and disadvantaged communities—and corroborate documented US coverage patterns. Future studies need to investigate school and community factors that may contribute to such patterns, in order to identify potential mechanisms and design appropriate interventions to increase vaccine coverage.

In the current study, the safety of the 2014/2015 Northern Hemisphere formulation of Vaxigrip® (Sanofi Pasteur) was assessed to satisfy European Union requirements. Individuals ⩾6 months of age eligible for seasonal influenza vaccination were included. Children 6 months–8 years of age received one dose (0.25 ml for 6–35 mo; 0.5 ml for 3–8 y) on day 0, and those who were previously unvaccinated received a second dose of the same volume on day 28. Participants ⩾9 years of age received one full dose (0.5 ml) on day 0. Frequency categories for solicited reactions were compared with historical data for the closest age group available. A total of 527 participants were included (6 mo–5 y, n = 106; 6–12 y, n = 105; 13–17 y, n = 106; 18–65 y, n = 105; >65 y, n = 105). Frequency categories were higher in this study than for the historical comparator for fever (very common vs. common) in participants 6 months–5 years of age; shivering (very common vs. common), rash (uncommon vs. very rare), and grade 3 injection-site induration (common vs. uncommon) in participants 6–12 years of age; and shivering in participants 13–17 years of age (very common vs. common) and >65 years of age (very common vs. common). However, these increases were not considered clinically significant because confidence intervals for proportions were overlapping and because most of the reactions were of grade 1 to 2 and resolved rapidly and spontaneously. No treatment-related serious adverse events were recorded and no safety concerns or safety signals were detected. These results indicate that the 2014/2015 Northern Hemisphere formulation of Vaxigrip was well tolerated and safe to use in all age groups, with no specific concerns identified, although the study was not powered to detect rare or very rare events.

While the clinical evidence of vaccine benefits is generally well established, the argument on the broader economic benefits resulting from investments in vaccines and immunization programs is murky and oftentimes, not well articulated. This is mostly true for low and middle-income countries. In this article, we examined literature evaluating both narrow and broad economic benefits of vaccines in LMICs from January 2000 to October 2016. A total of 177 studies were reviewed. Of these, 146 (82%) focused on understanding short-term direct and indirect impact (narrow economic benefits) of vaccines and 31 (18%) examined broader economic benefits which included willingness to pay for vaccines, outcome-related productivity gains, and savings accrued from preventing vaccine preventable disease (VPD) outbreaks. Virtually all studies reviewed concluded that implementation of various vaccine strategies were cost saving, cost-effective or, both cost saving and highly cost-effective under varying assumptions. The studies were further analyzed under three broad vaccine categories which included those focusing on new and underutilized vaccines 125 (71%), vaccines at the prequalification stage 31 (17%) and the traditional vaccines deployed through the Expanded Programme on Immunization such as pentavalent diphtheria-pertussis-tetanus, and those against polio, tuberculosis and measles which accounted for 21 (12%) of the studies. There was unequal geographic distribution of these studies when analyzed by World Health Organization regions. Regions like the Eastern Mediterranean and Europe had fewest studies completed (6) and (7) respectively. The lack of a standardized methodology and assumptions made cross-study comparisons and also broad generalization of some of the conclusions difficult. Most studies indicate that investments in immunization programs are cost effective and in some cases cost saving. Studies were skewed to narrow economic benefits. Wide variations in methods and assumptions made cross-country/study and regions comparisons difficult to achieve.