Current requirements indicated on the websites for organisations sending volunteers to work in the Ebola outbreak in West Africa.

<p>(The websites for Save the Children and UK-Med also indicate that they are recruiting volunteers, but we could find no indication of their requirements [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120013#pone.0120013.ref024" target="_blank">24</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120013#pone.0120013.ref028" target="_blank">28</a>]).</p><p>Current requirements indicated on the websites for organisations sending volunteers to work in the Ebola outbreak in West Africa.</p

Barriers and enablers to going to West Africa to help with the Ebola outbreak for four groups of respondents.

<p>The importance of each issue is indicated on a 5 point Likert scale from strongly disagree to strongly agree, for those who were considering going but had not yet decided (<i>“Considering”</i>); those who had not considered going (<i>“Not Considered”</i>); those who had considered it and decided not to go (<i>“Decided Against”</i>); those who had volunteered and were waiting to go (“<i>Volunteered</i>”), and those who had already been (“<i>Already Been</i>”). Issues marked * were introduced in the second version of the questionnaire from 22^nd October onwards (1450 responses). Data are the percentage of respondents giving the answers indicated; and the rank is indicated showing how important that issue was for that group. The values from which the figure is derived are given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120013#pone.0120013.s007" target="_blank">S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120013#pone.0120013.s008" target="_blank">S2</a> Tables.</p

Triplot showing the relationships between barriers and explanatory variables for the group of health workers who are considering going to West Africa, but have not volunteered.

<p>Solid blue lines represent barriers; dashed grey lines show explanatory variables. Angles between variables represent their correlations. All the explanatory variables shown have a significant influence on the barriers. RDA 1 and 2 refers to the first two redundancy analysis axes. Circles indicate variables which remained closely correlated across all redundancy analysis axes (equivalent to rotating this figure through different dimensions) that represent significant variation in the dataset (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120013#pone.0120013.s002" target="_blank">S1 Fig</a>. for plots of the 2^nd and 3^rd redundancy analysis axes). SSA experience = experience working in sub-Saharan Africa; previous experience = previous experience of Ebola; related experience = experience of a related transmissible haemorrhagic fever but not Ebola; professional experience = increasing years of experience since primary healthcare qualification. N = 321 respondents from both versions of the questionnaire. Analyses of the additional barriers added in the 2^nd version were conducted separately, but did not alter the correlations highlighted (data not shown).</p

Demographic information for all the respondents who completed the survey, divided according to the answer to whether they have considered going to West Africa to help in the current Ebola virus epidemic.

<p>Data are numbers (percent).</p><p>Demographic information for all the respondents who completed the survey, divided according to the answer to whether they have considered going to West Africa to help in the current Ebola virus epidemic.</p

Targeting of IFNγ responses to JEV SA14-14-2.

<p>(A) Sum of all responding pools (IFNγ SFC/10⁶ PBMC by ELISpot) against the number of responding pools at the time of maximum ELISpot response per participant in the study. (B) Number of participants responding to each protein of JEV in ELISpot assays, normalised to the protein size as responses per 100 amino acids. (C & D) Peptide pools were deconvoluted by <i>ex-vivo</i> ELISpot, or in ICS assays using T cell lines expanded to peptide pools. Location of epitopes mapped to individual peptides (C) and to “mini-pools” spanning regions 46–90 amino acids in size (D). The Y axes represent the number of responses identified (one of the six “mini-pool” regions identified was recognised by two participants). Subsets were determined by flow cytometry. CD4⁺ responses: green bars; CD8⁺ responses: blue bars. The single grey bar in (C) depicts a response identified by ELISpot where the subset was not determined.</p

Cytokine production by JE vaccine specific T cells by intracellular cytokine staining (ICS).

<p>(A) Magnitude of T cell cytokine responses to JEV SA14-14-2 detected by flow cytometry/ICS in five participants showing positive responses. Data are the percentage of cells in the parent (CD4⁺/CD8⁺) gate staining for the indicated cytokine, above unstimulated values. Filled circles = CD4⁺ responses, open circles = CD8⁺ responses. Bars = median value of CD4⁺ responses only. (B) SPICE analysis of CD4⁺ T cell responses detected by flow cytometry. Data are the proportion of the response comprised of IFNγ⁺/IL2⁺/TNFα⁺ triple positive cells (red pie slices), double positive cells (yellow slices) and single positive cells (blue slices). Arcs indicate the proportion of the response producing individual cytokines: IFNγ (purple arcs), IL2 (green arcs) and TNFα (light grey arcs). Left pie chart: CD4⁺ responses at weeks 1–4 (n = 4), right pie chart: participant VA001/1 at week 16. Participant VA001/1 made a triple positive response at week 16 after vaccination, hence this participant is presented separately.</p

Sub-optimal cross-reactivity of anti-JEV vaccine IFNγ responses in a DENV exposed participant.

<p>(A) Reciprocal DENV PRNT₅₀ were measured for all four DENV serotypes by plaque assay on MK₂ cells. (B) NS3 peptide pool IFNγ-ELISpot and NAb responses during the course of the study. (C) IFNγ-ELISpot responses to individual peptides at baseline and 16 weeks. Grey bars = wild type pools or peptide (VVAAEMAEALRGLPVRY), black bars = vaccine pools or vaccine peptide (VVAAEMAEVLRGLPVRY), hatched bars = DENV/2/4WNV peptide (VVAAEMAEALRGLPIRY before vaccination, ALRGLPIRY after vaccination). ELISpot data are presented after subtraction of background values; all responses shown met the criteria for a positive assay (>50 IFNγ-SFC/10⁶ PBMC and double the negative control). The IFNγ-ELISpot response to the JE vaccine peptide was significantly smaller than the response to the wild type peptide at the end of the study (paired t-test). (D) IFNγ responses (percent IFNγ⁺ CD8⁺ T cells) of short-term T cell lines (TCL) expanded with JEV and variant peptides before vaccination, and (E) IFNγ responses of TCL 16 weeks after vaccination, tested against both JEV and variant peptides. The peptides used before vaccination were VVAAEMAEALRGLPVRY (JEV) and VVAAEMAEALRGLPIRY (WNV, epitope in common with DENV2/4). After vaccination, TCL were expanded with minimal peptides ALRGLPVRY (JEV) and ALRGLPIRY (DENV2/4, WNV) but tested against library peptides VVAAEMAEALRGLPVRY (wild type JEV) and VVAAEMAEVLRGLPVRY (JE vaccine) in addition to ALRGLPIRY (DENV2/4, WNV).</p

Antibody and cellular responses to JE vaccine SA14-14-2.

<p>(A) Neutralisation of JEV SA14-14-2 by sera from vaccinated participants at 4 weeks, 8 weeks and 4–6 months after vaccination. Data are the logarithm of the geometric mean of 1/plaque reduction neutralisation titre 50% (PRNT₅₀) ± 95% confidence interval (CI). Filled circles = responders, open circles = non-responders. The number of participants with data at each time point are indicated. (B) IFNγ-ELISpot responses to a peptide library of JEV SA14-14-2 after vaccination. Data are the geometric mean of the sum of spot forming cells (SFC)/10⁶ PBMC for all responding pools (per participant) after subtraction of background wells at each time point ± 95% CI. Non-responding pools were not included. The number of participants is indicated as in (A). Responses were significantly increased over baseline at weeks 1, 2 and 4 (Wilcoxon signed rank test). (C) Proliferation responses in 13 JE vaccinated individuals. Data represent the average % responding cells (CFSE^lo/CD38^hi) measured by flow cytometry across all peptide pools tested in the CD4⁺ (filled circles) or CD8⁺ (open circles) gate. Data points are the median and error bars depict the interquartile range (IQR). The number of participants is indicated as in (A).</p

Summary of cross reactive T cell responses identified after vaccination with JEV SA14-14-2.

<p>Summary of cross reactive T cell responses identified after vaccination with JEV SA14-14-2.</p

Table_1_Age- and sex-specific differences in immune responses to BNT162b2 COVID-19 and live-attenuated influenza vaccines in UK adolescents.xlsx

IntroductionThe key to understanding the COVID-19 correlates of protection is assessing vaccine-induced immunity in different demographic groups. Young people are at a lower risk of COVID-19 mortality, females are at a lower risk than males, and females often generate stronger immune responses to vaccination.MethodsWe studied immune responses to two doses of BNT162b2 Pfizer COVID-19 vaccine in an adolescent cohort (n = 34, ages 12–16), an age group previously shown to elicit significantly greater immune responses to the same vaccine than young adults. Adolescents were studied with the aim of comparing their response to BNT162b2 to that of adults; and to assess the impacts of other factors such as sex, ongoing SARS–CoV–2 infection in schools, and prior exposure to endemic coronaviruses that circulate at high levels in young people. At the same time, we were able to evaluate immune responses to the co-administered live attenuated influenza vaccine. Blood samples from 34 adolescents taken before and after vaccination with COVID-19 and influenza vaccines were assayed for SARS–CoV–2-specific IgG and neutralising antibodies and cellular immunity specific for SARS–CoV–2 and endemic betacoronaviruses. The IgG targeting influenza lineages contained in the influenza vaccine were also assessed.ResultsRobust neutralising responses were identified in previously infected adolescents after one dose, and two doses were required in infection-naïve adolescents. As previously demonstrated, total IgG responses to SARS–CoV-2 Spike were significantly higher among vaccinated adolescents than among adults (aged 32–52) who received the BNT162b2 vaccine (comparing infection-naïve, 49,696 vs. 33,339; p = 0.03; comparing SARS-CoV–2 previously infected, 743,691 vs. 269,985; p DiscussionThese findings may result from the introduction of novel mRNA vaccination platforms, generating patterns of immunity divergent from established trends and providing new insights into what might be protective following COVID-19 vaccination.</p