Positively a good thing.
The Oxford University Hospital system conducted an enlightening observational study with PCR screening every 2 weeks for 6 months on healthcare workers following a positive (n=1265) or negative (n=11,364) test for anti-spike antibodies. The rate of contracting SARS-CoV-2 among the antibody-negative was 1.09 per 10,000 days at risk, with roughly half being symptomatic. Compare that to 0.13 per 10,000 days at risk among the antibody-positive, translating to 2 asymptomatic and 0 symptomatic cases. | Lumley, N Engl J Med 2020