Long-Term SARS-CoV-2-Specific Humoral and T Cell Responses after the BNT162b2 or BBIBP-CorV Booster and the Incidence of Breakthrough Infections among Healthcare Workers.

The effectiveness of COVID-19 vaccines developed against the original virus strain deteriorated noticeably in efficacy against the Omicron variant (B.1.1.529). Moreover, the immunity developed after vaccination or due to natural infection rapidly waned. In the present study, covering this period, we summarize the incidence of breakthrough infections among healthcare workers (HCWs) with respect to administration of the three vaccine doses. Additionally, we evaluate the long-term SARS-CoV-2-specific humoral and T cell responses at two different time points: six and twelve months after receipt of the third (booster) dose. The spike-protein-specific antibody levels and the quantity of structural-protein-specific T cells were evaluated at these time points and compared with the values measured earlier, 14 days after the booster vaccination. The study participants were categorized into two cohorts: Members of the first cohort received a two-dose BNT162b2 mRNA-based vaccine regimen, followed by an additional BNT162b2 booster six months later. Individuals in the second cohort received an inactivated-virus-based BBIBP-CorV booster six months after the initial two-dose BNT162b2 vaccination. Overall, 64.3% of participants were infected with SARS-CoV-2 confirmed by PCR or antigen test; however, additional subjects from the first cohort (23%) who did not know about their previous infection but had an anti-nucleocapsid T cell response were also considered virus-experienced. According to our results, no statistically significant difference was found between the two cohorts regarding the SARS-CoV-2-specific T cell response, neutralizing anti-RBD IgG, and anti-S IgA serum antibody levels either six or twelve months after receiving the booster, despite the overall higher median values of the first cohort. The only significant difference was the higher anti-S1/S2 IgG antibody level in the first cohort one year after the BNT162b2 booster (p = 0.039). In summary, the BNT162b2 and BBIBP-CorV boosters maintain durable humoral and T cell-mediated immune memory even one year after application. Although the booster provided limited protection against Omicron breakthrough infections, as 73.6% of these infections occurred after the booster vaccination, which means 53.5% cumulative incidence, it still offered excellent protection against severe disease and hospitalization in both cohorts.

Diagnosis of neuroborreliosis in the context of local seroprevalence: A chart review study and a methodological overview.

Background & objectives: In neuroborreliosis (NB) serology might objectively differentiate ongoing from past infection when the intrathecal space is involved. The hierarchy of the parallel serum-CSF (cerebrospinal fluid) methods is seldom discussed and remains elusive in daily practice. We compared the efficacy of certain methods and assessed the prevalence of anti-Borrelia antibodies in the local population. Methods: We summarized standard two-tier test results in all ELISA-reactive samples of patients with suspected NB (n=152) since 2017 and tested 122 unrelated sera for anti-Borrelia antibodies from central Hungary. Results: The most common central nervous system symptom was a cranial nerve palsy (27.6% of all subjects). CSF was available in 25 cases. A serum-CSF IgG-matched line immunoassay (LIA) detected intrathecal antibody production correctly in 6 of 8 samples when compared to the ELISA-based antibody-index (AI). Among the 122 random sera the prevalence of specific anti-Borrelia IgG antibodies (on LIA, not including anti-p41) were 6.8% above 30 and 10% above 60 years. Our results enable us to assume the predictive values of serological results according to the pretest probability of neuroborreliosis. Interpretation & conclusion: Our results suggest that recombinant antigen-based two-tier serology from solely the sera might have sufficient positive predictive value to verify NB in young individuals with characteristic anamnestic data in our region. When parallel serum-CSF testing is warranted, AI should have priority. IgG and albumin concentrations in the both serum and the CSF, the potential time of exposure and the nature and duration of symptoms form the bare minimal set of data for conclusive testing.

The potential impact of Helicobacter pylori seropositivity on recombinant antigen-based Lyme serology.

We assessed the impact of Helicobacter pylori seropositivity on recombinant antigen-based Lyme serology. We compared the IgG ELISA+LIA (line immunoassay) reactivity of anti-Helicobacter IgG positive and negative samples. The ELISA S/Co values and LIA band numbers were identical. Our results suggest that Helicobacter seropositivity lacks an apparent effect on Lyme disease test reactivity.