Dear Editor:

Recently, we published a letter entitled “What is the long-term clinical significance of anti-SARS-CoV-2-specific IgG?” about the rapid decay total levels and neutralizing anti-SARS-CoV-2 antibodies in asymptomatic and mild patients.¹ Nevertheless, with the increase in vaccination worldwide, we would like to add a few comments to our previous letter.

Post-infection patients develop increased antibodies against two major SARS-CoV-2 viral proteins, spike, and nucleocapsid.² Since the beginning of the pandemic, passive immunization with plasma derived from patients recovered from COVID-19 has been used as a virus-specific therapeutic intervention. A recent randomized trial with 288 patients hospitalized with severe COVID-19 pneumonia verified no significant differences in the clinical status or mortality in the treatment with placebo or convalescent plasma.³ A possible explanation is that the levels of neutralizing antibodies and the duration that anti-SARS-CoV-2 antibodies levels remain high for a very short period after natural infection and antibody production is dependent on the severity of the infection.⁴ Therefore, these factors may affect the efficiency of the treatment with convalescent plasma. Alternatively, the usage of anti-SARS-CoV-2 monoclonal antibodies to treat COVID-19 patients presented promising results, but it may be limited by the costs and production capacity.⁵ With the beginning of the vaccination process worldwide, we would like to propose an alternative to the convalescent plasma: the vaccinated plasma.

With the vaccination process, the numbers of cases and deaths by COVID-19 are expected to drop, once “herd immunity” is established. Nevertheless, due to the limitations of the overall production and distribution of the vaccines, this process could take years. Therefore, due to the current health, economic and social disruption caused by the pandemic^{6, 7} investigating treatments for COVID-19 patients is a necessary process.^{8, 9} Vaccination produces a safe and effective immune response to COVID-19, with high titers of neutralizing anti-SARS-CoV-2 IgG antibodies.¹⁰

Therefore, the use of vaccinated plasma could present an important, safe, and more effective intervention in comparison with convalescent plasma. Indeed, the effectiveness of this procedure still needs to be investigated, as well as proper dosage and timing of the plasma transfer in relation to the infection day. Nevertheless, we believe that this could represent a promising strategy in the current pandemic situation, which should be discussed by the audience of this prestigious journal.

CONFLICT OF INTEREST

All authors have no conflicts of interest to declare.

AUTHOR CONTRIBUTIONS

Gabriela Gama Freire Alberca: Visualization (equal); Writing – original draft (equal); Writing – review and editing (equal). Ricardo Wesley Alberca: Conceptualization (lead); Supervision (equal); Visualization (equal); Writing – original draft (equal); Writing – review and editing (equal).