Enhanced SARS-CoV-2 BA.2.86 Neutralization After BA.5 Infection in Vaccinated Kidney Transplant Recipients

Vaccination with mRNA vaccines has significantly reduced the SARS-CoV-2 mortality rate in the general population. However, the effectiveness of mRNA vaccines in kidney transplant (KTx) recipients is unclear.

In this cohort, we compared the disease severity and seroconversion rate after SARS-CoV-2 infection in 30 vaccinated and 8 unvaccinated KTx recipients. KTx recipients have infected between February 2022 and September 2023 during the Omicron variant phases. We measured anti-SARS-CoV-2 spike protein IgG antibodies (cutoff value was 1.0 AU/mL). Furthermore, we investigated anti-SARS-CoV-2 spike protein IgG antibodies and the neutralizing antibody titer against BA.5 and BA.2.86 in 10 vaccinated KTx recipients before and after BA.5 infection.

The incidence of moderate disease was significantly higher in the unvaccinated group (P = .004). The median antibody titers after SARS-CoV-2 infection in vaccinated and unvaccinated KTx recipients were 244.5 (IQR: 43.5-757.8) and <1 (IQR: <1-<1) AU/mL, respectively (P < .0001). Surprisingly, none of the 5 patients with moderate disease developed detectable antibodies after infection. The antibody titers and neutralizing antibody titer against BA.5 and BA.2.86 variants in vaccinated KTx recipients increased significantly after BA.5 infection (S-IgG: P = .004, BA.5: P = .002, BA.2.86: P = .016).

Although vaccinated KTx recipients achieved IgG antibody and neutralizing antibody boost after SARS-CoV-2 infection, unvaccinated KTx recipients did not experience an increase in antibody titers and experienced more severe infections. Furthermore, KTx recipients acquired the neutralizing activity against Omicron BA.2.86 after Omicron BA.5 infection. Thus, vaccination should be recommended for KTx recipients.