During the omicron wave, unvaccinated Americans had much higher rates of COVID-19 cases and hospitalization than fully vaccinated people -- especially those who received a booster shot, officials said Tuesday.
In a new report published by the Centers for Disease Control and Prevention, researchers from the Los Angeles County Department of Public Health looked at county-level COVID data between Nov. 7, 2021 and Jan. 8, 2022.
They found that in the 14-day period ending Dec. 11 -- the last period in which the delta variant was dominant -- COVID case rates in Los Angeles were 12.3 times higher among the unvaccinated compared to boosted individuals. Hospitalization rates were 83 times higher.
By the time the omicron variant became dominant, the rate ratios were lower, but still showed that vaccinated people are much more protected.
During the week ending Jan. 8, unvaccinated people had infection rates 3.6 times higher than people who had received boosters and hospitalization rates were 23 times higher.
Additionally, fully vaccinated people in Los Angeles who had not received a booster had COVID case rates that were twice as low and hospitalization rates 5.3 times lower than the unvaccinated group.
The report found that, over the course of the two-month study period, nearly 423,000 COVID-19 cases were reported in Los Angeles County residents aged 18 and older.
Of the cases, 33.6% were among the unvaccinated, 53.2% were among the fully vaccinated without a booster and 13.3% were among fully vaccinated people who had received a booster.
It's worth noting that, as of Jan. 8, 71% of county residents were fully vaccinated, according to county health department data. This means there will be a higher risk of breakthrough infections due to the higher absolute number of people being vaccinated.
Nearly 3% of unvaccinated individuals were hospitalized, 0.5% were admitted to the ICUs and 0.3% died of the virus, according to the report.
By comparison, 1% of fully vaccinated people without a booster and 0.7% of people with a booster were hospitalized.
Additionally, 0.12% of unboosted people and 0.08% of boosted people were admitted to ICUs and 0.05% and 0.03% died, respectively.
The report found that, during the omicron wave 6,743.5 per 100,000 unvaccinated people were contracting COVID-19 and 187.8 per 100,000 were hospitalized.
Among fully vaccinated people without a booster, rates were lower at 3,355.5 per 100,000 for COVID-19 cases and 35.4 per 100,000 for hospitalizations.
Rates were lowest among fully vaccinated people with a booster at 1,889 per 100,000 for infections and and 8.2 per 100,00 for hospitalizations.
"These findings align with those from recent studies, indicating that COVID-19 vaccination protects against severe COVID-19 caused by … variants, including omicron," the authors wrote in the report. "Efforts to promote COVID-19 vaccination and boosters are critical to preventing COVID-19–associated hospitalizations and severe outcomes.
The CDC has previously released similar estimates on the high risks for the unvaccinated when it comes to the omicron variant.
A report published last month from the agency found unvaccinated adults had a three times higher risk of infection than fully vaccinated adults and five times higher risk than those who had also been boosted.