Evolution of neutralizing antibodies and cross-activity against different variants of SARS-CoV-2 in patients recovering from COVID-19.

BACKGROUND: Patients recovering from COVID-19 may need vaccination against SARS-CoV-2 because acquired immunity from primary infection may wane, given the emergence of new SARS-CoV-2 variants. Understanding the trends of anti-spike IgG and neutralizing antibody titers in patients recovering from COVID-19 may inform the decision made on the appropriate interval between recovery and vaccination. METHODS: Participants aged 20 years or older and diagnosed with COVID-19 between January and December, 2020 were enrolled. Serum specimens were collected every three months from 10 days to 12 months after the onset of symptom for determinations of anti-spike IgG and neutralizing antibody titers against SARS-CoV-2 Wuhan strain with D614G mutation, alpha, gamma and delta variants. RESULTS: Of 19 participants, we found a decreasing trend of geometric mean titers of anti-spike IgG from 560.9 to 217 and 92 BAU/mL after a 4-month and a 7-month follow-up, respectively. The anti-spike IgG titers declined more quickly in the ten participants with severe or critical disease than the nine participants with only mild to moderate disease between one month and seven months after SARS-CoV-2 infection (-8.49 vs - 2.34-fold, p < 0.001). The neutralizing activity of the convalescent serum specimens collected from participants recovering from wild-type SARS-CoV-2 infection against different variants was lower, especially against the delta variants (p < 0.01 for each variant with Wuhan strain as reference). CONCLUSION: Acquired immunity from primary infection with SARS-CoV-2 waned within 4-7 months in COVID-19 patients, and neutralizing cross-activities against different SARS-CoV-2 variants were lower compared with those against wild-type strain.

Evolution of SARS-CoV-2 neutralizing antibody in an HIV-positive patient with COVID-19.

We presented the clinical course and immune responses of a well-controlled HIV-positive patient with COVID-19. The clinical presentation and antibody production to SARS-CoV-2 were similar to other COVID-19 patients without HIV infection. Neutralizing antibody reached a plateau from 26th to 47th day onset but decreased on 157th day after symptoms.

Experience of the use of hydroxychloroquine on patients with COVID-19: A perspective on viral load and cytokine kinetics.

Until now, there are no approved treatment against COVID-19. Hydroxychloroquine (HCQ) was hypothesized to be active against SARS-CoV2 via antiviral and anti-inflammatory effect; however, HCQ for COVID-19 in clinical use remained debating. In this preliminary report, we presented six patients with mild to moderate COVID-19. They were treated with HCQ for 14 days from the day of COVID-19 diagnosis. Serial viral load from respiratory specimens were performed every other day. Cytokine profile was checked before HCQ initiation and on the 14th day of HCQ treatment. All patients receiving HCQ completed 14-day course without complication. Among the six patients, the mean duration from symptom onset to last detectable viral load was 34 ± 12 days, which was similar to those without specific treatment in previous reports. Low level of interferon-gamma was noted in all patients of different stage of infection and three patients had elevation of IL-17 level. Prolonged virus shedding is still observed regardless HCQ. The impact of HCQ on cytokine kinetics remained unclear; however, IL-17 could be an inflammatory marker for disease status monitor and a potential therapeutic target.