Administration Of Yellow Fever Vaccine Research Articles

Safe administration of yellow fever vaccine in patients with suspected egg allergy.

The evidence available in the literature on the administration and safety of the yellow fever vaccine in patients with egg allergy is limited. We sought to describe the administration of yellow fever vaccine in children with suspected egg allergy using a simplified protocol. Children referred to the service from February 2018 to January 2020 with a history of possible egg allergy were classified as probably egg-allergic or not on the basis of history and specific IgE testing. A vaccine prick test was performed only in those with a history of an anaphylactic reaction to egg ingestion and if the result was positive the vaccine was administered in a 2-step protocol (2 equal doses of 0.25 mL with an interval of 30 minutes between the 2 applications). All other children received the vaccine as a single dose. A total of 435 children were evaluated; 48.27% were probably not allergic, and 51.72% were probably allergic to egg, of which 32.88% were considered anaphylactic. A total of 414 (95.2%) children had no vaccine reactions. Of the 21 (4.8%) children who had some reaction, 10 experienced a local reaction, 9 a mild skin reaction distant from the vaccine site, 1 presented local cutaneous reaction distant to the vaccination site, and 1 patient developed possible anaphylaxis. The vaccine prick test did not predict a vaccine reaction (odds ratio, 1.29; 95% CI, 0.25-6.72; P= .67). Yellow fever vaccine can be safely administered as a single dose in children with a confirmed or suspected egg allergy.

Pneumococcal conjugate vaccination schedules in infants\u2014acquisition, immunogenicity, and pneumococcal conjugate and yellow fever vaccine co-administration study

BackgroundPneumococcal conjugate vaccines (PCVs) effectively prevent pneumococcal disease, but the global impact of pneumococcal vaccination is hampered by its cost. The evaluation of reduced dose schedules of PCV includes measurement of effects on immunogenicity and carriage acquisition compared to standard schedules. The relevance and feasibility of trials of reduced dose schedules is greatest in middle- and low-income countries, such as The Gambia, where the introduction of PCV resulted in good disease control but where transmission of vaccine-type pneumococci persists. We designed a large cluster-randomised field trial of an alternative reduced dose schedule of PCV compared to the standard schedule, the PVS trial. We will also conduct a sub-study to evaluate the individual-level effect of the two schedules on carriage acquisition, immunogenicity, and co-administration of PCV with yellow fever vaccine, the PVS-AcqImm trial.MethodsPVS-AcqImm is a prospective, cluster-randomised trial of one dose of PCV scheduled at age 6 weeks with a booster dose at age 9 months (i.e. alternative ‘1+1’ schedule) compared to three primary doses scheduled at 6, 10, and 14 weeks of age (i.e. standard ‘3+0’ schedule). Sub-groups within the alternative schedule group will receive yellow fever vaccine separately or co-administered with PCV at 9 months of age. The primary endpoints are (a) rate of nasopharyngeal vaccine-type pneumococcal acquisition from 9 to 14 months of age, (b) geometric mean concentration of vaccine-type pneumococcal IgG at 18 months of age, and (c) proportions with yellow fever neutralising antibody titre ≥8 four weeks after administration of yellow fever vaccine. Participants and field staff will not be masked to group allocation while the measurement of laboratory endpoints will be masked. Approximately equal numbers of participants will be resident in each of 28 geographic clusters (14 clusters in alternative and standard schedule groups); 784 enrolled for acquisition measurements and 336 for immunogenicity measurements.DiscussionAnalysis will account for potential non-independence of measurements by cluster and so interpretation of effects will be at the individual level (i.e. a population of individuals). PVS-AcqImm will evaluate whether acquisition of vaccine-type pneumococci is reduced by the alternative compared to the standard schedule, which is required if the alternative schedule is to be effective. Likewise, evidence of superior immune response at 18 months of age and safety of PCV co-administration with yellow fever vaccine will support decision-making regarding the use of the alternative 1+1 schedule. Acquisition and immunogenicity outcomes will be essential for the interpretation of the results of the large field trial comparing the two schedules.Trial registrationInternational Standard Randomised Controlled Trial Number 72821613.

Safety of yellow fever vaccine administration in confirmed egg-allergic patients

Yellow fever vaccine (YFV) is recommended in endemic areas but represents a risk for egg-allergic patients, as it is cultivated in embryonated eggs. This study aims to describe the outcomes of yellow fever vaccination in patients with confirmed egg allergy (EA). Methods:A prospective study was conducted from January 2018 to September 2019. EA was diagnosed through positive oral food challenge (OFC), recent history of anaphylaxis following egg contact (anaphylaxis in the last 6 months) or immediate allergic reaction in the last 2 months with positive specific IgE. A skinprick test (SPT) with YFV was performed. If the SPT was negative, an intradermal test (ID) was performed at a 1:100 dilution. If the ID was negative, a full dose of YFV was administered. If the skin prick test or ID were positive, the YFV was administered using a graded dosing protocol. Results: It was included 58 patients with confirmed egg allergy (36 M:22F), with a median age of 2.3 years (0.7–13.9 y/o). Forty-two patients had a positive OFC. Nine reported recent anaphylaxis. The other 7 had reactions in the last 2 months with positive specific IgE. During OFC, 15 presented anaphylaxis, while the other 27 presented hives and/or angioedema or vomiting. SPT with YFV was negative in all patients. ID was negative in 48 patients who uneventfully received a full dose of YFV. Ten patients had a positive ID and received YFV in graded doses. Six patients presented a mild reaction controlled with antihistamines, and 4 patients received the vaccine without reactions. Positive ID was significantly related to the vaccine reaction (p < 0.0001). Administration of YFV using a specific protocol was safe even in anaphylactic patients. However, we recommend performing the ID, which can help predict a higher risk of vaccine reaction. An appropriate setting is required to control adverse events.

Safety of yellow fever vaccine administration in confirmed egg-allergic patients

The yellow fever vaccine (YFV) is recommended in endemic areas but represents a risk for egg-allergic patients, as it is cultivated in chicken embryos. This study aims to describe the outcomes of yellow fever vaccination in patients with confirmed egg allergy (EA). Prospective study in a quaternary hospital, from January 2018 to September 2019. EA was diagnosed through oral food challenge (OFC) or recent history of anaphylaxis following egg contact (anaphylaxis in the last 6 months) or allergic reaction in the last 2 months with positive specific IgE. Skin prick test (SPT) with YFV was performed in all participants. If negative SPT, an intradermal test (ID) was performed at 1:100 dilution. If negative ID, a full dose of YFV was administered. If positive skin test, the YFV was administered using a graded-dose protocol. Among 100 patients with prior EA history, 58 were confirmed (36M:22F), median age of 2.35y (0,7 a 13,9Y). Forty-two patients had a positive OFC. Nine reported recent anaphylaxis. The other 7 had reaction in the last 2 months with positive specific IgE. During OFC, 15 presented anaphylaxis and the other (27) presented urticaria and/or angioedema or vomiting. SPT with YFV was negative in all patients. ID was negative in 48 patients, who received a full dose of YFV in usual manner, uneventfully. Ten patients had a positive ID and received the YFV in graded doses, six of them presented a mild reaction controlled with antihistamines and four patients received the vaccine without reactions. Positive ID was significantly related to vaccine reaction (p=0,0001). Administration of YFV using a specific protocol was safe even in anaphylactic patients. We only recommend performing the ID test which contributed to predicting a higher risk of vaccine reaction. An appropriate setting is required in order to control adverse events.

Mitigating yellow-fever-vaccine-associated viscerotropic disease in older travellers

Following two recent fatal yellow fever vaccine associated adverse reactions, a review of the safety of the yellow fever vaccine was undertaken in the UK. While the review found the administration of yellow fever vaccine remained favourable for most travellers, when used as indicated, a number of changes to clinical practice were mandated.

To err is human: Clinical incident calls to a national travel health advice line

The National Travel Health Network and Centre (NaTHNaC) offers a telephone advice line for travel health practitioners in the UK. In this study we review clinical incidents concerning vaccines or malaria prophylaxis reported between 2016 and 2018.Two-hundred-and-fifty-one clinical incident calls were recorded, and commonly concerned scheduling or dosing errors. Vaccine scheduling errors accounted for 103 calls (41%), predominantly due to hepatitis A or hepatitis B vaccination either alone or in combination (65/103, 63%). Administration of yellow fever vaccine within 28 days of measles, mumps and rubella accounted for a further 15 (15%) calls. Twenty-six (10%) calls reported administration of a vaccine that was not recommended either for the destination or contraindicated in the traveller. Yellow fever was the commonest single vaccine discussed in 28.4% of vaccine clinical incidents reported. By highlighting common mistakes, we hope to raise awareness of common issues and improve practice in travel health.

Successful Administration of Yellow Fever Vaccine in Egg-allergic Patients

Successful Administration of Yellow Fever Vaccine in Egg-allergic Patients

Yellow fever vaccine used in a psoriatic arthritis patient treated with methotrexate: a case report

The yellow fever vaccines on the market are contraindicated for immunocompromised and elderly patients. A case of yellow fever vaccine used in a 27-year-old Slovenian male with psoriatic arthritis during treatment with methotrexate is described. We demonstrate a positive case, since there were no adverse effects in concurrent administration of yellow fever vaccine and methotrexate. This patient did not show severe adverse reactions and did not contract yellow fever despite potential exposure. More research is needed on possible adverse effects of concurrent administration of yellow fever vaccine and methotrexate to determine the potential of this method for more frequent use.

Dynamics of the CD8+ T cell response to a model of acute viral infection (VIR4P.1017)

Abstract During an acute viral infection T cells specific to viral antigens, as determined by the T-cell receptor (TCR), activate and expand. To determine the breadth of immune response to infection, and to understand recruitment to immunological memory, characterizing the TCR repertoire before, during, and after a model of acute viral infection is necessary. Here we use the yellow fever vaccine (YFV) to model acute viral infection. Blood was collected from 9 subjects at 0, 14, and 90 days after YFV administration. In addition to isolating PBMC for all time points, we sorted for YFV-specific effector T-cells at day 14 and for central and effector memory T-cells in 6 of 9 subjects at day 90. For each sample, gDNA was extracted and the TCR repertoire was assayed by high-throughput TCRβ sequencing. Expanded T cell clones can specifically bind a pathogen-derived epitope (specific), or receive proliferation signals without antigen-specificity (bystander). YFV-specific clones were identified by enrichment in the YFV-specific day 14 sort vs. day 14 PBMC; in each subject, we estimate that the antigen-specific immune response comprises approximately 103 T cell clones. Bystanders were identified as clones expanding from day 0 to day 14 PBMC that are not YFV-specific. Many more YFV-specific clones were recruited to memory at day 90 than bystander clones (40% vs. 3%), indicating that antigen specificity, rather than just proliferation, is a major determinant of memory recruitment.

Administration of Yellow Fever Vaccine in Patients with Egg Allergy

Background: The population of large parts of Africa, South America and travellers to these areas are at risk of yellow fever (YF) with a 50% mortality risk. Yellow fever vaccine (YFV) propagated in hens' eggs confers protection in 95% of the vaccinated. The rate of anaphylaxis for YFV ranges from 0.42 to 1.8/100,000 doses with most cases considered to be due to egg allergy. Egg allergy is a contraindication for the YFV. Nevertheless, the potential fatal sequelae from YF give the incentive to protect everyone at risk irrespective of their allergic status. Methods: Six subjects who had had a recent reaction to egg and who were travelling to endemic areas (3 adults and 3 children) underwent skin prick tests (SPT) with undiluted YFV and egg extract. Intradermal tests for YFV were undertaken at a 1:10 dilution. In 4 egg-allergic patients with a positive SPT to YFV, a 7-step desensitization protocol was used. A 2-step (10 + 90%) protocol was used in the 2 subjects with a negative YFV SPT. Premedication was not administered. Results: All 6 patients were successfully vaccinated. Four patients completed desensitization: 1 developed mild local erythema at the injection site, 1 had fleeting generalized urticaria with local erythema/angioedema and 2 did not experience any adverse reactions. Patients who received YFV in 2 steps developed no adverse reactions. Conclusions: We describe the successful administration of YFV in 6 egg-allergic patients. The Cambridge Allergy 7-step protocol allows for its safe administration in patients with positive SPT to YFV. A 2-step protocol can be used in patients with negative YFV SPT.

Does yellow fever 17D vaccine protect against melanoma?

BCG vaccine, vaccinia vaccine and certain pathogens that were shown in previous studies to protect against melanoma have antigenic determinants homologous in their amino acids sequence with the melanoma antigen HERV-K-MEL, encoded by a human endogenous retrovirus K (HERV-K), which is expressed in about 95% of malignant melanocytes. Yellow fever vaccine (YFV) likewise contains an antigenic determinant with a close homology to HERV-K-MEL and might therefore also confer protection against melanoma. To investigate this possibility we carried out a cohort study (28,306 subjects) and a nested case-control study (37 melamona cases and 151 tumors not expressing HERV-K-MEL) in Veneto region (North-Eastern Italy). The standardized incidence ratio was 1.33 (95% confidence interval, 0.84–2.11), 1.59 (0.97–2.59) and 0.59 (0.19–1.84), while the age- gender-adjusted odds ratios were 1.00, 0.96 (0.43–2.14) and 0.26 (0.07–0.96), at 0–4, 5–9, and ≥10 years elapsed from YFV administration, respectively. The risk of melanoma may therefore be lowered 10 years after vaccination with yellow fever vaccine.

ENCEPHALITIS AFTER YELLOW FEVER VACCINATION

A case of encephalitis after yellow fever vaccination in a young infant is reported. The results of efforts to identify a virus and the probable etiology are discussed. From the negative results of attempts at virus isolation and from epidemiologic criteria, it is concluded that there is a cause and effect relationship between the administration of yellow fever vaccine and the occurrence of subsequent encephalitis in this infant.