Serological response to tick-borne encephalitis (TBE) vaccination in the elderly – results from an observational study

Jílková, E; Vejvalková, P; Stiborová, I; Skorkovský, Jiří; Král, Vlastimil

doi:10.1517/14712590903066711

Cited by 41 publications

(19 citation statements)

References 21 publications

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“…Since all our study participants from the Åland Islands had been vaccinated with the FSME-IMMUN vaccine, we could not investigate if there was any difference in sensitivity and specificity with regard to the Enzygnost and Immunozym assay as an effect of homologous or heterogeneous TBEV strains in the vaccine and ELISA assays, as reported by Jílková et al [28]. The discrepancy between the Immunozym assay compared to the Enzygnost and RFFIT assay is fully accounted for by the difference in cut-off levels chosen as shown by the ROC curve analysis.…”

Section: Discussionmentioning

confidence: 99%

“…The Novartis Encepur vaccine on the other hand, uses the K23 TBEV strain, as does the Enzygnost ELISA assay. A study by Jílková et al [28] found that the results differed significantly between the two ELISA assays depending on whether the TBEV strain was heterologous or homologous with respect to the vaccine used. Neutralizing antibody tests do not suffer from this potential bias and are considered to be the best surrogate marker of protection against TBEV [27], [29].…”

Section: Introductionmentioning

confidence: 99%

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Factors Determining Immunological Response to Vaccination against Tick-Borne Encephalitis Virus in Older Individuals

et al. 2014

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We performed a cross-sectional study including 533 individuals (median age 61) from the highly TBE endemic Åland Islands in the archipelago between Sweden and Finland. Blood samples, questionnaires and vaccination records were obtained from all study participants. The aim was to investigate if there was any association between TBEV antibody titer and 12 health-related factors. Measurement of TBEV IgG antibodies was performed using two commercial ELISA assays (Enzygnost and Immunozym), and a third in-house rapid fluorescent focus inhibition test was used to measure TBEV neutralizing antibodies. The age of the individual and the number of vaccine doses were the two most important factors determining the immunological response to vaccination. The response to each vaccine dose declined linearly with increased age. A 35 year age difference corresponds to a vaccine dose increment from 3 to 4 to achieve the same immunological response. Participants previously vaccinated against other flaviviruses had lower odds of being seropositive for neutralizing TBEV antibodies on average, while participants with self-reported asthma had higher odds of being seropositive. By comparing the 3 serological assays we show that the Enzygnost and Immunozym assay differ due to choice of cutoffs, but not in overall accuracy.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Factors Determining Immunological Response to Vaccination against Tick-Borne Encephalitis Virus in Older Individuals

et al. 2014

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“…The K23 and Neudoerfl strains are used in the European vaccines Encepur (Novartis Vaccines and Diagnostics GmbH & Co., Marburg, Germany) and FSME-Immun (Baxter AG, Vienna, Austria), respectively. Both vaccines induce neutralizing antibodies against all three subtypes of TBEV, but there might be some differences in reactivity depending on whether homologous or heterologous coating antigens were used for the vaccine (14,15).…”

Section: Discussionmentioning

confidence: 99%

Comparison of Two Commercial Tick-Borne Encephalitis Virus IgG Enzyme-Linked Immunosorbent Assays

Weissbach¹,

Hirsch²

2015

Clin. Vaccine Immunol.

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Despite the availability of protective vaccines, tick-borne encephalitis virus (TBEV) infections have been increasingly reported to the European Centre for Disease Prevention and Control in the past 2 decades. Since the diagnosis of TBEV exposure relies on serological testing, we compared two commercial enzyme-linked immunosorbent assays (ELISAs), i.e., Immunozym FSME IgG assay (ELISA-1) and Euroimmun FSME Vienna IgG assay (ELISA-2). Both assays use whole TBEV antigens, but they differ in viral strains (Neudoerfl for ELISA-1 and K23 for ELISA-2) and cutoff values. In testing of samples from 398 healthy blood donors, ELISA-1 showed higher reactivity levels than ELISA-2 (P < 0.001), suggesting different assay properties. This finding was supported by Bland-Altman analysis of the optical density at 450 nm (OD 450 ) (mean bias, ؉0.32 [95% limits of agreement, ؊0.31 to ؉0.95]) and persisted after transformation into Vienna units. Concordant results were observed for 276 sera (69%) (44 positive and 232 negative results). Discordant results were observed for 122 sera (31%); 15 were fully discordant, all being ELISA-1 positive and ELISA-2 negative, and 107 were partially discordant (101 being ELISA-1 indeterminate and ELISA-2 negative and 6 having positive or indeterminate reactivity in both ELISAs). Neutralization testing at a 1:10 dilution yielded positive results for 33 of 44 concordant positive sera, 1 of 15 fully discordant sera, and 1 of 33 partially discordant sera. Indirect immunofluorescence testing revealed high antibody titers of >100 for yellow fever virus in 18 cases and for dengue virus in one case, suggesting that cross-reactivity contributed to the ELISA-1 results. We conclude that (i) cross-reactivity among flaviviruses remains a limitation of TBEV serological testing, (ii) ELISA-2 revealed reasonable sensitivity and specificity for anti-TBEV IgG population screening of human sera, and (iii) neutralization testing is most specific and should be reserved for selective questions. Despite the availability of protective vaccines, tick-borne encephalitis (TBE) has been increasingly reported in Europe over the past 2 decades (1). According to a recent analysis by the European Centre for Disease Prevention and Control (ECDC), 29,381 cases of TBE have been diagnosed in 16 countries of the European Union (EU)/European Free Trade Association (EFTA) since the year 2000. The annual rates range from 2,000 to 3,500 cases per year, showing a net increase despite a remarkable and as yet unexplained 3-year peak periodicity. Climate changes, with milder winters and earlier and prolonged summer seasons, and increasing numbers of small rodent and larger wild and domestic animal hosts, such as deer, sheep, and goats, are thought to contribute to expanding areas in which tick-borne encephalitis virus (TBEV)-infected ticks are endemic, which facilitates human exposure during occupational and leisure activities outdoors (2-4). The notable exception to this European trend is Austria, where TBEV vaccination has been effectively ...

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“…Jilkova et al recently found that 18% of individuals aged 60 years or above had antibody concentrations below putative protective levels after 2 of the first 3 vaccinations required for primary immunization [27]. A study on TBE booster vaccination reporting 6-year follow-up data showed that antibody levels were 2 times lower in vaccinees 60 years of age or older, implying some waning of antibodies with increasing age [28].…”

Section: Tbe and The Ageing Immune Systemmentioning

confidence: 99%

Tick-borne encephalitis and golden agers: position paper of the International Scientific Working Group on Tick-borne encephalitis (ISW-TBE)

Jelenik

Keller

Briggs

et al. 2010

Wien Med Wochenschr

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One of the primary goals of the 11th Annual Meeting of the International Scientific Working Group on Tick-borne encephalitis (ISW-TBE) held in 2009 was to develop the first update of the Position Paper on TBE in Golden Agers, summarizing the most essential aspects of the disease in this age group. TBE morbidity has continued to increase in recent years, which is thought to be due to an interplay of social, political, ecological, economic and demographic factors combined with climate changes. Today's golden agers i.e. individuals aged 50 years or above, are healthier and more mobile, lead more active lifestyles and spend more time travelling and performing outdoor leisure activities. This places them at an increased risk of infection. At the same time, increasing age is associated with a quantitative and qualitative decline in innate and adaptive immunity, which is why elderly individuals are more susceptible to infection and severe disease than younger people. Also, their response to vaccination tends to be slower, antibody titres generally reach lower levels and titres tend to decrease earlier than in younger individuals. Evidence is accumulating that this is also the case with TBE vaccination, emphasizing the importance of administering the first TBE booster vaccination no later than 3 years after the completion of primary immunization or at an even shorter interval. Encouragingly, recent data have shown that the field effectiveness of TBE vaccination exceeds 97%, with no significant differences between age groups.

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Serological response to tick-borne encephalitis (TBE) vaccination in the elderly – results from an observational study

Abstract: After two doses of TBE vaccine, one in five persons aged 60 years or older may be without protective antibodies, confirming the importance of testing the antibody response after the second vaccination and administering an additional dose in the event of insufficient response.

Cited by 41 publications

References 21 publications

Factors Determining Immunological Response to Vaccination against Tick-Borne Encephalitis Virus in Older Individuals

Factors Determining Immunological Response to Vaccination against Tick-Borne Encephalitis Virus in Older Individuals

Comparison of Two Commercial Tick-Borne Encephalitis Virus IgG Enzyme-Linked Immunosorbent Assays

Tick-borne encephalitis and golden agers: position paper of the International Scientific Working Group on Tick-borne encephalitis (ISW-TBE)

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