Sero-survey on long-term care facility residents reveals increased risk of sub-optimal antibody response to BNT162b2: implications for breakthrough prevention.

BACKGROUND: The impact of coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) on residents of long-term care facilities (LTCFs) has been dramatic on global scale as older age and comorbidities pose an increased risk of severe disease and death. METHODS: Aim of this study was to evaluate SARS-CoV-2 Spike-specific IgG (S-IgG) antibody titers in 478 residents and 649 health care workers of a large Italian long-term care facility two months after complete vaccination with BNT162b2. Associations among resident-related factors and predictors of humoral response were investigated. RESULTS: By stratifying levels of humoral responses, we found that 62.1%, 21.6%, 12.1% and 4.2% of residents had high (>1,000 BAU/ml), medium (101-1,000), low (1-100) and null (<1 BAU/mL) S-IgG titers, respectively. Residents with documented previous COVID-19 and those with SARS-CoV-2 nucleocapsid-specific IgG (N-IgG) positive serology showed higher level of serological response, while significant associations were observed for cancer with suboptimal response (p = 0.005) and the administration of corticosteroid for suboptimal response (p = 0.028) and a null one (p = 0.039). According to multivariate logistic regression, predictors of an increased risk of null response were advanced age (Odd ratio, OR: 2.630; Confidence interval, CI: 1.13-6.14; p = 0.025), corticosteroid therapy (OR: 4.964; CI: 1.06-23.52; p = 0.042) and diabetes mellitus (OR:3.415; CI:1.08-10.8; p = 0.037). In contrast, previous diagnosis of COVID-19 was strongly associated with a reduced risk of null response to vaccination (OR:0.126; CI:0.02-0.23; p < 0.001). CONCLUSIONS: SARS-CoV-2 specific antibodies in elderly individuals should be consider when deciding the need of a third dose of vaccine for prevention of reinfections in LTCFs despite the maintenance of barrier measures.

Durability of Humoral Responses after the Second Dose of mRNA BNT162b2 Vaccine in Residents of a Long Term Care Facility.

Residents of long-term care facilities (LTCFs) have been dramatically hit by the COVID-19 pandemic on a global scale as older age and comorbidities pose an increased risk of severe disease and death. The aim of the study was to assess the quantity and durability of specific antibody responses to SARS-CoV-2 after the first cycle (two doses) of BNT162b2 vaccine. To achieve this, SARS-CoV-2 Spike-specific IgG (S-IgG) titers was evaluated in 432 residents of the largest Italian LTCF at months 2 and 6 after vaccination. By stratifying levels of humoral responses as high, medium, low and null, we did not find any difference when comparing the two time points; however, the median levels of antibodies halved overtime. As positive nucleocapsid serology was associated with a reduced risk of a suboptimal response at both time points, we conducted separate analyses accordingly. In subjects with positive serology, the median level of anti-S IgG slightly increased at the second time point, while a significant reduction was observed in patients without previous exposure to the virus. At month 6, diabetes alone was associated with an increased risk of impaired response. Our data provide additional insights into the longitudinal dynamics of the immune response to BNT162b2 vaccination in the elderly, highlighting the need for SARS-CoV-2 antibody monitoring following third-dose administration.

Risk of failure in patients with 215 HIV-1 revertants starting their first thymidine analog-containing highly active antiretroviral therapy.

OBJECTIVE: To investigate the impact of 215 HIV-1 revertants on the risk of virological failure of the first thymidine analog-containing highly active antiretroviral therapy (HAART). DESIGN: The study included 491 HIV-1 subjects of the Italian Cohort Naive for Antiretrovirals, 405 of whom received a genotypic assay before therapy and had a virological follow-up. METHODS: Pre-treatment genotypic resistance was assessed by sequencing of the whole protease (PR) and reverse transcriptase (RT) region. RESULTS: Three (3.2%) and 13 (3.3%) individuals with recent (n = 95) and chronic (n = 396) HIV-1 infection carried an HIV-1 strain with 215 revertants (215D/C/E/A/V), respectively. In contrast, nucleoside associated mutations were higher in the former (15.8%) compared with the latter group (6.8%) (P = 0.005). A multivariable regression model, considering pre-HAART viral load levels, use of saquinavir-hard gel as the only PI, use of zidovudine, number of other RT and PR mutations, indicated that patients carrying 215 revertants had an increased risk of virological failure compared with those not carrying such mutants (adjusted relative hazard = 2.97 95% confidence interval, 1.11-7.94, P = 0.03). Among patients with 215 revertants, who experienced virological failure, four out of seven showed the emergence of the 215Y resistant mutation. The probability of 215Y occurrence was different between patients carrying 215 revertants compared with those who did not carried these mutants (P = 0.006). CONCLUSIONS: HIV-1 215 revertants with an increased ability for selecting 215Y mutation are associated with a higher risk of virological failure and may lead to the appearance of virus carrying 215Y/F mutation in vivo. These findings suggest that 215 revertant viruses may compromise the efficacy of the first thymidine analog-containing regimen.