Coadministered pneumococcal conjugate vaccine decreases immune response to hepatitis A vaccine: a randomized controlled trial.

OBJECTIVES: We explored the influence of coadministration on safety and immunogenicity of the most common travellers' vaccine hepatitis A (HepA) and the pneumococcal conjugate vaccine (PCV) increasingly used both at home and before travel. METHODS: Volunteers aged ≥18 years (n = 305) were randomly assigned 1:1:1 into three groups receiving: 13-valent PCV (PCV13) + HepA, PCV13, or HepA. Anti-pneumococcal IgG concentrations, opsonophagocytic activity (OPA) titres, and total hepatitis A antibody (anti-HAV) concentrations were measured before and 28 ± 3 days after vaccination. Adverse events (AEs) were recorded over 4 weeks. RESULTS: After vaccination, the anti-HAV geometric mean concentration was significantly lower in the PCV13+HepA than the HepA group: 34.47 mIU/mL (95% CI: 26.42-44.97 mIU/mL) versus 72.94 mIU/mL (95% CI: 55.01-96.72 mIU/mL), p < 0.001. Anti-HAV ≥10 mIU/mL considered protective was reached by 71 of 85 (83.5%) in the PCV13+HepA group versus 76 of 79 (96.2%) in the HepA group, p 0.008. The increases in anti-pneumococcal IgG and OPA levels were comparable in the PCV13+HepA and PCV13 groups, apart from a bigger rise in the PCV13+HepA group for serotype 3 (one-way ANOVA: serotype 3 IgG p 0.010, OPA p 0.002). AEs proved more frequent among those receiving PCV13 than HepA, but simultaneous administration did not increase the rates: ≥one AE was reported by 45 of 56 (80.4%) PCV13, 43 of 54 (79.6%) PCV13+HepA, and 25 of 53 (47.2%) HepA recipients providing structured AE data. DISCUSSION: Coadministration of HepA and PCV13 did not cause safety concerns, nor did it impact the patients' response to PCV13, apart from serotype 3. However, coadministered PCV13 significantly impaired antibody responses to HepA.

Superspreading of SARS-CoV-2 Omicron BA.2.23 among vaccinated Finnish adults: symptomatic COVID-19 only contracted by those without recent infection.

An outbreak of SARS-CoV-2 was confirmed after an academic party in Helsinki, Finland, in 2022. All 70 guests were requested to fill in follow-up questionnaires; serologic analyses and whole-genome sequencing (WGS) were conducted when possible.Of those participating - all but one with ≥3 vaccine doses - 21/53 (40%) had test-confirmed symptomatic COVID-19: 7% of those with earlier episodes and 76% of those without. Half (11/21) were febrile, but none needed hospitalisation. WGS revealed subvariant BA.2.23.Compared to vaccination alone, our data suggest remarkable protection by hybrid immunity against symptomatic infection, particularly in instances of recent infections with homologous variants.

Safety and immunogenicity of ETVAX®, an oral inactivated vaccine against enterotoxigenic Escherichia coli diarrhoea: a double-blinded, randomized, placebo-controlled trial amongst Finnish travellers to Benin, West Africa.

BACKGROUND: No licensed human vaccines are available against enterotoxigenic Escherichia coli (ETEC), a major diarrhoeal pathogen affecting children in low- and middle-income countries and foreign travellers alike. ETVAX®, a multivalent oral whole-cell vaccine containing four inactivated ETEC strains and the heat-labile enterotoxin B subunit (LTB), has proved promising in Phase 1 and Phase 1/ 2 studies. METHODS: We conducted a Phase 2b double-blinded, randomized, placebo-controlled trial amongst Finnish travellers to Benin, West Africa. This report presents study design and safety and immunogenicity data. Volunteers aged 18-65 years were randomized 1:1 to receive ETVAX® or placebo. They visited Benin for 12 days, provided stool and blood samples and completed adverse event (AE) forms. IgA and IgG antibodies to LTB and O78 lipopolysaccharide (LPS) were measured by electrochemiluminescence. RESULTS: The AEs did not differ significantly between vaccine (n = 374) and placebo (n = 375) recipients. Of the solicited AEs, loose stools/diarrhoea (26.7/25.9%) and stomach ache (23.0/20.0%) were reported most commonly. Of all possibly/probably vaccine-related AEs, the most frequent were gastrointestinal symptoms (54.0/48.8%) and nervous system disorders (20.3/25.1%). Serious AEs were recorded for 4.3/5.6%, all unlikely to be vaccine related. Amongst the ETVAX® recipients, LTB-specific IgA antibodies increased 22-fold. For the 370/372 vaccine/placebo recipients, the frequency of ≥2-fold increases against LTB was 81/2.4%, and against O78 LPS 69/2.7%. The majority of ETVAX® recipients (93%) responded to either LTB or O78. CONCLUSIONS: This Phase 2b trial is the largest on ETVAX® undertaken amongst travellers to date. ETVAX® showed an excellent safety profile and proved strongly immunogenic, which encourages the further development of this vaccine.

Kinetics of Neutralizing Antibodies of COVID-19 Patients Tested Using Clinical D614G, B.1.1.7, and B 1.351 Isolates in Microneutralization Assays.

Increasing evidence suggests that some newly emerged SARS-CoV-2 variants of concern (VoCs) resist neutralization by antibodies elicited by the early-pandemic wild-type virus. We applied neutralization tests to paired recoveree sera (n = 38) using clinical isolates representing the first wave (D614G), VoC1, and VoC2 lineages (B.1.1.7 and B 1.351). Neutralizing antibodies inhibited contemporary and VoC1 lineages, whereas inhibition of VoC2 was reduced 8-fold, with 50% of sera failing to show neutralization. These results provide evidence for the increased potential of VoC2 to reinfect previously SARS-CoV-infected individuals. The kinetics of NAbs in different patients showed similar decline against all variants, with generally low initial anti-B.1.351 responses becoming undetectable, but with anti-B.1.1.7 NAbs remaining detectable (>20) for months after acute infection.