Declining Levels of Neutralizing Antibodies Against SARS-CoV-2 in Convalescent COVID-19 Patients One Year Post Symptom Onset

Abstract

Major advances have been made in understanding the dynamics of humoral immunity briefly after the acute coronavirus disease 2019 (COVID-19). However, knowledge concerning long-term kinetics of antibody responses in convalescent patients is limited. During a one-year period post symptom onset, we longitudinally collected 162 samples from 76 patients and quantified IgM and IgG antibodies recognizing the nucleocapsid (N) protein or the receptor binding domain (RBD) of the spike protein (S). After one year, approximately 90% of recovered patients still had detectable SARS-CoV-2-specific IgG antibodies recognizing N and RBD-S. Intriguingly, neutralizing activity was only detectable in ~43% of patients. When neutralization tests against the E484K-mutated variant of concern (VOC) B.1.351 (initially identified in South Africa) were performed among patients who neutralize the original virus, the capacity to neutralize was even further diminished to 22.6% of donors. Despite declining N- and S-specific IgG titers, a considerable fraction of recovered patients had detectable neutralizing activity one year after infection. However, neutralizing capacities, in particular against an E484K-mutated VOC were only detectable in a minority of patients one year after symptomatic COVID-19. Our findings shed light on the kinetics of long-term immune responses after natural SARS-CoV-2 infection and argue for vaccinations of individuals who experienced a natural infection to protect against emerging VOC.

Long-Lasting Immunity Against SARS-CoV-2: Dream or Reality?

“…Our results reveal that in most cases, SARS-CoV-2 S-specific IgG levels remained stable over time and SARS-CoV-2 NCP-specific IgG levels decreased to a stable level within 6–12 months after symptom onset, while their range continuously diminished. Recent studies show that SARS-CoV-2-specific antibody levels after an infection were detectable in the majority of donors over a period of up to 1 year, even though the rate of recession varied ( 9 , 11 , 12 , 26 , 27 ). This supports our findings from the long-term analysis.…”

“…This supports our findings from the long-term analysis. Some studies show only similar progressions for anti-S and anti-N antibody levels over time ( 26 , 27 ) whereas a study by Wang and colleagues assessed anti-RBD as well as anti-N antibodies and found stable levels of anti-RBD IgG compared to a reduction of anti-N IgG levels ( 11 ). This has also been observed in our results which suggest that the descent of anti-N IgG levels is more pronounced in comparison to the course of anti-S IgG.…”

A Retrospective Survey among SARS-CoV-1 Infected Healthcare Workers after Three Years Post-Infection

“…In convalescent SARS-CoV-2 infected individuals, evidence showed that nAbs can sustain for over a year and exhibited a longer duration of detectable antibody with severe disease patients; however, the nAbs responses were not affected by different age groups [ 17 ]. This may be due to individuals infected with SARS-CoV-2 with older age having higher chances to develop severe diseases presentation, thus generating higher titer of nAbs [ 17 , 18 , 19 ]. We did not observe statistical differences of anti-N or anti-S existence status in HCWs with and without ARDS in our cohort.…”

A review: Antibody-dependent enhancement in COVID-19: The not so friendly side of antibodies

“…84 In addition to this, there are reports regarding the kinetics of natural immunity in patients who had COVID-19. In a study, 85 the humoral response was evaluated in a total of 76 patients (IgM and IgG antibodies that recognized the nucleocapsid protein or the RBD of the S-protein). In these patients 1 year after infection, approximately 90% of recovered patients still had detectable SARS-CoV-2-specific IgG antibodies recognizing N and RBD-S.…”