A prospective, non-inferiority, multicenter study (VOICE trial) carried out by S. Oosting et al. found that messenger RNA (mRNA)-1273 vaccine is safe against coronavirus in cancer patients receiving chemotherapy, immunotherapy, or chemo-immunotherapy for solid tumors and resulted in a high seroconversion rate that was comparable to the control group (people without cancer).

Cancer patients have an elevated risk of complications from SARS-CoV-2 infections. Therefore, researchers aimed to explore the safety and immunogenicity of the messenger RNA-1273 COVID-19 vaccine in cancer people who were being treated for solid tumors.

Participants were divided into four cohorts: (i) Cohort A: People without cancer, (ii) Cohort B: People with solid tumors who were given immunotherapy, (iii) Cohort C: Patients treated with chemotherapy, and (iv) Patients treated with chemo-immunotherapy. The recruited people were given 2 doses of the vaccine twenty-eight days apart.

The major outcome was coronavirus Spike S1-specific IgG serum antibody response, defined as >10 binding antibody units (BAU)/ml 28 days following the 2^nd  vaccination. The SARS-CoV-2 neutralizing capacity of these antibodies, adverse events, and coronavirus Spike-specific interferon-gamma T cell response were also examined.

Notably 743 out of 791 people were evaluable for the major outcome parameter in cohort A (n=240), B (n=131), C (n=229) and D (n=143). Table 1 illustrates the percentage of people in which SARS-CoV-2-binding antibody response was noted. For distinguishing between adequate and suboptimal responders, a cut-off level at 300 BAU/ml was defined on the basis of neutralizing capacity.

In cohorts A, B, C, and D, the antibody response was noted to be adequate in 66%, 37.1%, 32.5%, and 33.3% of people respectively after the 1st vaccination. After the second vaccination, the  antibody response is depicted in Table 1:

In 46.7% of suboptimal and non-responders, the spike-specific T cell responses were noted. There were no novel safety signals.

For each of the cohort with solid tumors, the percentage of people having a SARS-CoV-2-binding antibody response after 2 vaccinations showed non-inferiority in comparison with people without cancer. But, a considerable minority lacks a satisfactory response. The majority of the people exhibited a rise in antibody concentration after 2^nd vaccination. Thus, an additional booster might turn inadequate responders into adequate responders.