Serum-IgG Responses to SARS-CoV-2 After Mild and Severe COVID-19 Infection

Patients with severe symptoms and patients with mild symptoms of COVID-19 both develop SARS-CoV-2-specific IgG antibodies in serum (according to clinical trials). Patients with severe COVID-19 both seroconvert earlier and develop higher concentrations of SARS-CoV-2-specific IgG than patients with mild symptoms. Seroconverted patients with both mild and severe symptoms should still have detectable IgG levels after more than 75 days. A small percentage of patients with mild disease failed to produce detectable levels of IgG (more than 90 days PSO), but virus-neutralizing antibodies (NAbs) against SARS-CoV-2 were detected in all of these patients in the trials.

Concentrations of serum IgG over time in patients with Severe (Red) and Mild (Blue) disease (Cut-off for positive sample indicated by dotted line) in clinical trial:

PLOS ONE | https://doi.org/10.1371/journal.pone.0241104 October 21, 2020

Assessing mRNA Vaccine’s Level of Protection Against Covid-19

SARS-CoV-2 Antibody-Binding and Neutralization Responses Following mRNA Vaccination

We have a diverse group of people who are getting vaccinated, different age groups with different underlying health conditions. We need to assess the long-term durability of immunogenicity and the magnitude of antibody, cellular, and memory responses for at least 12 months following the second vaccination.

A two-dose regimen of vaccination should confer 95% protection against Covid-19 in persons 16 years of age or older. Safety over a median of 2 months was similar throughout all available mRNA viral vaccines in the clinical trials.

Virus neutralizing monoclonal antibodies (VNMA) are made in a laboratory to act like natural antibodies to limit the amount of virus in your body. VNMA infusion is specifically directed against the spike protein of SARS-CoV-2 and administered to patients with recently diagnosed Covid-19. They are designed to block the virus’ attachment and entry into human cells.

VNMA treatment with bamlanivimab or casirivimab/imdevimab is used for people who have mild to moderate symptoms. Analysis in clinical trials after infusion of VNMA appeared to accelerate the natural decline in viral load.