BNT162b vaccines are immunogenic and protect non-human primates against SARS-CoV-2

A safe and effective vaccine against COVID-19 is urgently needed in quantities sufficient to immunise large populations. We report the preclinical development of two BNT162b vaccine candidates, which contain lipid-nanoparticle (LNP) formulated nucleoside-modified mRNA encoding SARS-CoV-2 spike glycoprotein-derived immunogens. BNT162b1 encodes a soluble, secreted, trimerised receptor-binding domain (RBD-foldon). BNT162b2 encodes the full-length transmembrane spike glycoprotein, locked in its prefusion conformation (P2 S). The flexibly tethered RBDs of the RBD-foldon bind ACE2 with high avidity. Approximately 20% of the P 2S trimers are in the two-RBD down, one-RBD up state. In mice, one intramuscular dose of either candidate elicits a dose-dependent antibody response with high virus-entry inhibition titres and strong TH1 CD4+ and IFN{gamma}+ CD8+ T-cell responses. Prime/boost vaccination of rhesus macaques with BNT162b candidates elicits SARS-CoV-2 neutralising geometric mean titres 8.2 to 18.2 times that of a SARS-CoV-2 convalescent human serum panel. The vaccine candidates protect macaques from SARS-CoV-2 challenge, with BNT162b2 protecting the lower respiratory tract from the presence of viral RNA and with no evidence of disease enhancement. Both candidates are being evaluated in phase 1 trials in Germany and the United States. BNT162b2 is being evaluated in an ongoing global, pivotal Phase 2/3 trial (NCT04380701, NCT04368728).

COVID-19 experience: first Italian survey on healthcare staff members from a Mother-Child Research hospital using combined molecular and rapid immunoassays test

The fast spread of the novel coronavirus (SARS-CoV-2) has become a global threat hitting the worldwide fragile health care system. In Italy, there is a continued COVID-19 growth of cases and deaths that requires control measures for the correct management of the epidemiological emergency. To contribute to increasing the overall knowledge of COVID-19, systematic tests in the general population are required. Here, we describe the first Italian survey performed in 727 employees belonging to a Mother-Child Research hospital tested for both viral (nasopharyngeal and oropharyngeal swabs) and antibody presence. Individuals were divided into three risk categories (high, medium and low) according to their job activity. Only one subject was positive at the swab test while 17.2% of the cohort was positive for the presence of antibodies. Results highlighted that the presence of Positive antibodies is significantly associated with high and medium risk exposure occupation (p-value=0.026) as well as cold and conjunctivitis symptoms (p-value=0.016 and 0.042 respectively). Moreover, among healthcare professionals, the category of medical doctors showed a significant association with the presence of antibodies against SARS-CoV-2 (p-value=0.0127). Finally, we detected a rapid decrease in antibody intensity between two assessments performed within a very short period (p-value=0.009). Overall, the present study increases our knowledge of the epidemiological data of COVID-19 infection in Italy, suggesting a high prevalence of immune individuals (i.e. at least among at-risk categories) and the efficacy of the combined diagnostic protocol to monitor the possible outbreak.