ABSTRACT
Currently available COVID-19 mRNA vaccines have demonstrated high efficacy in clinical trials.1-3 However, cancer patients, including those with hematological malignancies, were largely excluded from these trials. In this prospective, observational study we measured anti-S protein IgG titers as well as avidity in lymphoma patients (n=67) vaccinated with a COVID-19 mRNA vaccine. Serological response rates in lymphoma patients who were treatment naïve (100% in CLL, 88.9% in other, non-CLL non-Hodgkin lymphoma patients), or who were last treated more than 24 months prior to vaccination (100% in CLL, 90% in other-NHL), were similar to healthy controls (100%). Patients on active therapy, however, had a diminished response rate (40% in CLL, 21.0% in other-NHL). No patient who received anti-CD20 monoclonal antibodies (mAb) within six months of vaccination responded. Thus, the utility of testing anti-S titers should be explored in patients on active therapy or with recent anti-CD20 mAb exposure, to assess their response to vaccination. We also propose studying passive protection with S-protein mAbs as an alternative prophylactic strategy for patients who respond poorly to vaccination.
Subject(s)
COVID-19ABSTRACT
Vaccines are critical for curtailing the COVID-19 pandemic. In the USA, two highly protective mRNA vaccines are available: BNT162b2 from Pfizer/BioNTech and mRNA-1273 from Moderna. These vaccines induce antibodies to the SARS-CoV-2 S-protein, including neutralizing antibodies (NAbs) predominantly directed against the Receptor Binding Domain (RBD). Serum NAbs are induced at modest levels within ~1 week of the first dose, but their titers are strongly boosted by a second dose at 3 (BNT162b2) or 4 weeks (mRNA-1273). SARS-CoV-2 is most commonly transmitted nasally or orally and infects cells in the mucosae of the respiratory and to some extent also the gastrointestinal tract. Although serum NAbs may be a correlate of protection against COVID-19, mucosal antibodies might directly prevent or limit virus acquisition by the nasal, oral and conjunctival routes. Whether the mRNA vaccines induce mucosal immunity has not been studied. Here, we report that antibodies to the S-protein and its RBD are present in saliva samples from mRNA-vaccinated healthcare workers (HCW). Within 1-2 weeks after their second dose, 37/37 and 8/8 recipients of the Pfizer and Moderna vaccines, respectively, had S-protein IgG antibodies in their saliva, while IgA was detected in a substantial proportion. These observations may be relevant to vaccine-mediated protection from SARS-CoV-2 infection and disease.