Virological and Serological Characterization of SARS-CoV-2 Infections Diagnosed After mRNA BNT162b2 Vaccination. (preprint)

Coronavirus disease 2019 (COVID-19) vaccines are proving to be very effective in preventing severe illness; however, although rare, post-vaccine infections have been reported. The present study describes 94 infections (47.9% symptomatic, 52.1% asymptomatic), occurred in Lazio Region (Central Italy) in the first trimester 2021, after first or second dose of mRNA BNT162b2 vaccine. Median viral load at diagnosis was independent from number and time of vaccine dose administration, despite the higher proportion of samples with low viral load observed in fully vaccinated individuals. More importantly, infectious virus was cultured from NPS collected from both asymptomatic and symptomatic vaccinated individuals, suggesting that, at least in principle, they can transmit the infection to susceptible people. The majority of the post-vaccine infections here reported, showed pauci/asymptomatic clinical course, confirming the impact of vaccination on COVID-19 disease. Most cases (78%) showed infection in presence of neutralizing antibodies at the time of infection diagnosis, presumably attributable to vaccination, due to the concomitant absence of anti-N IgG in most cases. The proportion of post-vaccine infections attributed either to Alpha and Gamma VOCs was similar to the proportion observed in the contemporary unvaccinated population in Lazio region. In addition, mutational analysis did not suggest enrichment of a defined set of Spike protein substitutions depending on the vaccination status. Characterization of host and virus factors associated with vaccine breakthrough, coupled with intensive and continuous monitoring of involved viral strains, is crucial to adopt informed vaccination strategies.

COVID-19 Disease - Temporal Analyses of Complete Blood Count Parameters Over Course of Illness, and Relationship to Patient Demographics and Management Outcomes in Survivors and Non-Survivors: A Longitudinal Descriptive Cohort Study (preprint)

Background: More detailed temporal analyses of complete (Full) blood count (CBC) parameters, their evolution and relationship to patient age, gender, co-morbidities and management outcomes in survivors and non-survivors with COVID-19 disease could help identify prognostic clinical biomarkers. Methods: From 29 January 2020 until 28 March 2020, we performed a longitudinal cohort study of COVID-19 inpatients at the Italian National Institute for Infectious Diseases, Rome, Italy. Nine CBC parameters as a continuous variable were studied [neutrophils, lymphocytes, monocytes, platelets, mean platelet volume, red blood cell count, haemoglobin concentration, mean red blood cell volume and red blood cell distribution width (RDW %)]. Model-based punctual estimates and difference between survivors and non-survivors, overall, and by co-morbidities, at specific times after symptoms, with relative 95% CI and P-values were obtained by marginal prediction and ANOVA-style joint tests. All analyses were carried out by STATA 15 statistical package. Main Findings: 379 COVID-19 patients [273 (72% were male; mean age was 61.67 (SD 15.60)] were enrolled and 1,805 measures per parameter were analysed. Neutrophil counts were on average significantly higher in non-survivors than in survivors (P<0.001) and lymphocytes were on average higher in survivors (P<0.001). These differences were time dependent. Reverse temporal trends were observed for lymphocyte and neutrophil counts in survivors and non-survivors. Average platelets counts (P<0.001) and median platelets volume (P<0.001) were significantly different in survivors and in non-survivors. The differences were time dependent and consistent with acute inflammation followed either by recovery or by death. Anaemia with anisocytosis were observed in the later phase of COVID-19 disease in non-survivors only. Mortality was significantly higher in patients with diabetes (p=0.005), obesity (p=0.010), chronic renal failure (p=0.001), COPD (p=0.033) cardiovascular diseases (p=0.001) and those >60 years(p=0.001). Age (p=0.042), obesity (p=0.002), chronic renal failure (p=0.002) and cardiovascular diseases (p=0.009) were independently associated with poor patient clinical outcome at 30 day after symptom onset. Interpretation: Increased neutrophil counts, reduced lymphocyte counts, higher median platelet volume, anemia with anisocytosis, in association with obesity, chronic renal failure, COPD, cardiovascular diseases and age >60 years predict poor prognosis in COVID19 patients.Funding Statement: Ricerca Corrente e Finalizzata Italy Ministry of Health, AIRC (IG2018-21880); Regione Lazio (Gruppi di ricerca, E56C18000460002).Declaration of Interests: The authors declare no competing interest.Ethics Approval Statement: This study was approved by the IRB of Italian National Institute for Infectious Diseases “Lazzaro Spallanzani” (INMI), in Rome (Italy).