Results from a new study in patients who had a mild COVID-19 infection, suggest that there is a wide variation in the level of neutralising antibodies (NAbs) produced.
Researchers from the Shanghai Public Health Clinical Centre, China, examined the association between mild infection with COVID-19 and the subsequent development of antibodies in a cohort of 175 patients with a mean age of 50 years (53% female) with mild disease and testing positive for the virus. Patients were hospitalised between January to February 2020 for a median of 16 days and had a median disease duration of 22 days.
At discharge, levels of NAbs, which are necessary for viral clearance, varied substantially and were even undetectable in ten patients and very low in 30% of patients. A total of 117 patients were available for a two-week follow-up appointment at which time, NAbs levels had decreased significantly compared with the levels at discharge and were still undetectable in the ten patients. An interesting find from the study was the NAbs were significantly higher in older compared to younger patients, and the former group also had higher C-reactive protein levels and lower lymphocyte levels at the time of admission.
The authors concluded that the clinical implications of their findings, especially in relation to the development of a vaccine, are currently unknown.
Reference
Wu F et al. Evaluating the association of clinical characteristics with neutralizing antibody levels in patients who have recovered from mild COVID-19 in Shanghai, China. JAMA Intern Med 2020; August 18: doi:10.1001/jamainternmed.2020.4616
