The second-infection cases were reported between Aug. 20 and Feb. 28 and involve people ranging in age from 1 to 101. For a case to be considered a second infection, the Centers for Disease Control and Prevention requires two positive molecular amplification tests, such as a PCR test, separated by at least 90 days.
Colorado health officials have identified 822 people who were infected twice with COVID-19 during the pandemic. The Colorado Department of Public Health and Environment added the case data to the state’s dashboard on Monday.
Health officials said separate COVID-19 infections are genetically different from one another. This can be difficult to determine, because most labs do not keep samples for more than a few days.
The quality of test results decreases the longer it is in storage and scientists say second infections often have a lower viral load, which impacts their ability to perform genetic sequencing.
So far, the state lab has sequenced 7 pairs of test specimens. Of those, 5 were genetically different, which confirms a secondary infection.
Health officials emphasize that the criteria to determine reinfection could change as scientists learn more about immunity to the virus.
“While reinfection is rare, it’s not unexpected based on what we know from similar viruses,” CDPHE stated in a news release.
The rollout of vaccines could also impact immunity to COVID-19. More than 482,000 Coloradans are fully vaccinated against the virus, which accounts for more than 8% of the state’s population.
Colorado is more than 99% of its way to vaccinating 70% of Coloradans ages 70 and up, a goal officials hoped to accomplish by the end of February. The state expects to receive 1.25 million vaccine doses this month, including 45,500 doses of the Johnson & Johnson vaccine by this Friday.
Doctors say Coloradans should continue to protect themselves, regardless of if they have already had COVID-19 by washing their hands, wearing a mask and social distancing.
CDPHE data as of 4 p.m. Monday:
Vaccines (Phase 1A & 1B):
- 907 Total Vaccine Providers
- 913,102 People Immunized with One Dose
- 482,442 People Immunized with Two Doses
- 1,449,455 Cumulative Doses Distributed
- 1,397,245 Cumulative Doses Administered
- 11,796 tests conducted on Feb. 28 with 3.40% positivity rate (7-day moving average)
- 5.29% daily positivity rate on Feb. 28
- 369 Patients currently hospitalized, 79% of facilities reporting (+11)
- 58 Patients under investigation for probable cases, not lab confirmed (+12)
- 48 Patients discharged/transferred in past 24 hours (+18)
- 9% Facilities anticipating staff shortages within next week (+0%)
- 1% Facilities anticipating PPE shortages within next week (+0%)
- 3% Facilities anticipating ICU bed shortages within next week (-1%)
- 28% Critical care ventilators in use (+1)
- 429,839 cases (+1,536)
- This includes 822 second-infections dating back to Aug. 2020 that CDPHE added to the dashboard on Monday.
- 100 Variants of concern (+0)
- 54 Variants under investigation (+0)
- 23,550 hospitalized (+74)
- 2,581,721 tested (+4,366)
- 6,229,855 test encounters (+13,654)
- 5,952 deaths among cases (+1)
- 5,903 deaths due to COVID-19 (+29)
- 3,893 outbreaks (+6)