Note: I noticed yesterday that the NC Office of State Budget and Management had on February 18 updated the July 2021 population estimate I have been using (10,753,496). I am now using the new population estimate of 10,658,717.

Here is the NC Threat-Free Index for the week ending March 21:

  • As of March 21, there were 864,755 North Carolinians presumed to be recovered from COVID-19
  • Active cases comprised just 2.4% of NC’s total case count (note: a case of COVID isn’t a permanent infection, and only someone with an active case of the virus can conceivably transmit it to you)
  • Active cases represented about 0.2% (two-tenths of one percent) of NC’s population (note: active cases are lab-confirmed cases of COVID-19 minus recoveries and deaths)
  • More than 24 out of every 25 (96.3%) of NC’s total cases were recovered, meaning they are no longer infectious
  • Only about 0.1% of people in NC had died with COVID-19 (regardless of the actual cause of death)
  • Meanwhile, about 91.6% people in NC had never had a lab-confirmed case of COVID-19, despite the PCR test cycle threshold set so high as to produce a large amount of false positives (note: this proportion will always decline, but we have been living with this virus since February 2020, as far as testing is concerned)
  • All things considered, about 99.8% of people in NC posed no threat of passing along COVID-19 to anyone — a virus most had never had and the rest had recovered from (note: this proportion will fluctuate based on relative growth in lab-confirmed cases vs. recoveries, and it is likely understated because it does not account for vaccinations)

A further note about vaccinations

DHHS lists that as of March 22, 28% of the state population 18+ year of age has been at least partially vaccinated, and that 17.8% of this population has been fully vaccinated. I don’t know how much overlap there is between recoveries and vaccinations. If people who have recovered from the virus (i.e., a natural vaccination) were a completely separate population from those who have been vaccinated, that would suggest that as of March 22, just over 24.2% of the state population was immune.

Even that statistic would likely be vastly undercounting state immunity, given how many mild infections (never diagnosed), exposures fought off due to preexisting immunity, and SARS-CoV-2 infections that people had prior to the virus being officially identified (diagnosed as influenza-like illnesses) there must have been.

With respect to immunity via previous SARS-CoV-2 infections and vaccinations, newly published research (March 19, 2021) in the Journal of the American Medical Association confirms expectations: antibodies from recovering from an infection and from the vaccine not only rapidly appear and persist for months and months, but also they ward off virus infections from new variants. Here’s the main finding:

This study found neutralizing activity of infection- and vaccine-elicited antibodies against 4 SARS-CoV-2 variants, including B.1, B.1.1.7, and N501Y. Because neutralization studies measure the ability of antibodies to block virus infection, these results suggest that infection- and vaccine-induced immunity may be retained against the B.1.1.7 variant. As additional variants emerge, neutralizing-antibody responses after infection and vaccination should be monitored.