LAS VEGAS (KLAS) — One-third of confirmed COVID-19 cases in Clark County in December were in fully vaccinated individuals 12 years and older, new data from the Southern Nevada Health District (SNHD) reveals.

A report from the health district indicates a fully vaccinated person is someone who received two doses of the Pfizer or Moderna vaccine, or one dose of Johnson & Johnson. It does not include any booster shot, according to the report.

The percentage of vaccinated individuals who are testing positive for COVID-19 has steadily increased since vaccines were widely introduced last spring. The good news, however, is hospitalizations do not appear to be soaring along with cases, indicating vaccines are working at preventing serious illness.

In May, less than 4% of COVID-19 cases in Clark County involved fully vaccinated individuals. By November, nearly a quarter of cases involved a person who was fully vaccinated, SNHD showed.

“Given the large number of people being vaccinated in the United States and the high level of ongoing SARS-CoV-2 circulation, thousands of symptomatic vaccine breakthrough cases are expected, even if the vaccines remain as effective as demonstrated during the clinical trials,” a note on the report states.

A chart of breakthrough cases also shows a large spike beginning in December. This increase coincides with the omicron variant’s introduction to the area.

The vaccines were developed to fight the initial COVID variant, not subsequent ones. As the data indicates, each variant becomes more immune against vaccines.

Doctors and medical professionals recommend getting vaccinated to avoid hospitalization and death.

Scientists have said the omicron variant spreads even easier than other coronavirus strains, including delta. The variant had already become the dominant strain in the U.S shortly before Americans celebrated the holidays and the New Year.

As of Dec. 29, SNHD reported nearly 20,000 breakthrough cases in Clark County since the beginning of the pandemic.

As of Dec. 29, SNHD reported 249 breakthrough deaths and 845 breakthrough hospitalizations.

To put those numbers into perspective, SNHD has reported 379,454 cases and 6,499 deaths over the course of the entire pandemic, during which vaccines were introduced a year in.

A chart of breakthrough cases also shows a large spike beginning in December. This increase coincides with the omicron variant’s introduction to the area. (KLAS)

As of last week, the unvaccinated were 18 times more likely to contract COVID-19 than the vaccinated, however, this data is reflective of the entire pandemic, not just with the omicron variant. In addition, the unvaccinated were 26 times more likely to die from COVID-19 than the vaccinated.

Early studies suggest that the vaccinated will need a booster shot for the best chance at preventing an omicron infection but that even without the extra dose, vaccination should still largely protect people from serious sickness or death.

About 33% of all Americans have received their booster shot, according to data to compiled by the Centers for Disease Control and Prevention. More than 62% of the population is considered fully vaccinated, according to CDC data.