With inputs from Dr Monica Vasudev

1003:  Pfizer will get $1.95 billion from the U.S. government to produce 100 million doses of their COVID-19 vaccine candidate. (Reuters)

1004: More data suggest that humoral immunity faded rapidly in people with mild COVID-19 illness. (New England Journal of Medicine)

1005: A small study points to rapid decay of anti–SARS-CoV-2 antibodies in individuals with mild COVID-19

DG Alert: A study has suggested that humoral immunity against SARS-CoV-2 may not last long among persons with mild illness. Investigators at University of California assessed 34 individuals, of whom, 30 had infection confirmed by PCR, while the other 4 had CLI.  Most of them had mild illness.

Thirty one of them had two serial measurements of IgG levels, while the remaining 3 underwent three serial measurements. The first measurement was obtained at a mean of 37 days from symptom onset (range, 18 to 65), and the last measurement was done at a mean of 86 days after symptom onset (range, 44 to 119).

Initial mean IgG level was 3.48 log10 ng per milliliter (range, 2.52 to 4.41). According to a linear regression model including the study participants’ age and sex, days from symptom onset to first measurement, and the first log10 antibody level, the estimated mean change (slope) was −0.0083 log10 ng per milliliter per day (range, −0.0352 to 0.0062). This corresponds to a half-life of about 73 days over the observation period. Investigators noted that the 95% confidence interval for the slope was −0.0115 to −0.0050 log10 ng per milliliter per day (half-life, 52 to 120 days).

The protective role of antibodies against SARS-CoV-2 is not clearly known; however, these antibodies are an acceptable correlate of antiviral immunity. The anti–receptor-binding domain antibody levels correspond to plasma viral neutralizing activity. Considering that early antibody decline following acute viral antigenic exposure is exponential, researchers noted that antibody loss that was quicker than that for SARS-CoV-1.

[Reference: https://www.nejm.org/doi/10.1056/NEJMc2025179]

1006: Treatment of AMI and acute stroke will be tenecteplase

The COVID-19 pandemic could speed up the shift to tenecteplase for stroke and AMI treatment as it is given as a single, 5-second IV bolus that takes about 2 minutes to mix, prepare, and administer compared to more than 1 hour for weight-based bolus and subsequent infusion of alteplase. [Medpage Today]

Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA