Third dose of anti-SARS-CoV-2 vaccine for patients with cancer: Should humoral responses be monitored? A position article

Abstract

Taking into account higher risk of severe coronavirus disease 2019 (COVID-19) or death among patients with cancer, as well as impaired immunogenicity following anti-SARS-CoV-2 vaccines, in addition to waning immunity, booster dosing appears mandatory in this patient population. This review sought to provide reasonable evidence so as to assist oncologists in their daily practice, helping them decide when an anti-SARS-Cov2 antibodies (Abs) dosage should be scheduled following a full two-dose vaccination and if necessary, propose an early third dose (D3). Such D3 could apply to non-responder patients with anti-Spike (S) Abs titers < 40 binding antibody units (BAU)/mL. For low-responder patients with anti-S Abs titers between 40 BAU/mL and 100/260 BAU/mL (suggested area of uncertainty), an early D3 may similarly be proposed. Nevertheless, this D3 could be administered in a less urgent manner, taking into account associated co-morbidities and regional epidemic incidence rates. This latter strategy may comprise a monthly dosage of anti-S titers so as to better assess the kinetics of waning immunity. For responder patients with anti-S titers above 260 BAU/mL, we suggest to follow the recommendations outlined for the general population. Given this context, patients with anti-S titers above 1000 BAU/mL should be given the possibility to undergo anti-S titer control after 3 months, designed to assess rapid humoral waning immunity. We strongly recommend that patients with cancer be included into observational serological monitoring studies or clinical trials that are dedicated to severe immunocompromised patients without any humoral seroconversion after D3.

Seropositivity and neutralising antibodies at six months after BNT162b2 vaccination in patients with solid tumours

“…Patients with cancer are at a significantly increased risk of severe morbidity and mortality from coronavirus disease of 2019 (COVID-19) [ [1] , [2] , [3] , [4] , [5] , [6] , [7] , [8] , [9] ]. In a previous report, we showed that an adequate antibody response was achieved after two doses of BNT162b2, but not after one, in patients with cancer vaccinated during anticancer therapy, and at lower seropositivity rates compared with healthy controls [ 10 ], in accordance with additional reports [ [11] , [12] , [13] , [14] , [15] ]. Conflicting data came from follow-up studies showing that seropositivity rates among patients with cancer compared with healthy controls were lower at four months after the second vaccine dose [ 16 ], but were similar at six months [ 17 ].…”

SARS-CoV-2 infection in cancer patients on active therapy after the booster dose of mRNA vaccines

“…The occurrence of COVID-19 after the booster dose in a sizeable proportion of cancer patients on active therapy requires attention, and needs to be further explored in large series investigated by international consortia. Nevertheless, the usefulness of a third vaccine dose in cancer patients seems to remain unquestionable at present ( 20 , 21 , 22 , 23 , 24 ), also due to the observed increase of neutralizing antibodies to the Omicron variant ( 10 , 11 , 12 ), and to the generally mild clinical course of SARS-CoV-2 infection we observed, complying with the aim of vaccination to reduce COVID-19-related hospitalizations and deaths. Consistently, the booster dose was reported to significantly associate with lower rates of symptomatic infections in healthy subjects compared to those who received only two vaccine doses ( 13 ).…”

Cumulative Incidence of SARS-CoV-2 in Healthcare Workers at a General Hospital in Germany during the Pandemic—A Longitudinal Analysis

“…After the second vaccine dose, only one serological non-responder was found (0.3%). In the literature, non-responders are described in patients with immune deficiencies [ 38 , 39 , 40 ]. We found no study that investigated non-responders in HW.…”