MADISON, Wis. — The number of fully vaccinated people in Wisconsin who were hospitalized with COVID-19 more than doubled from February to July, but the more contagious delta variant was still an exponentially greater threat to the unvaccinated, state Department of Health Services data released Thursday shows.

The unvaccinated were three-times as likely to test positive for COVID-19 as the vaccinated in July, the health department data showed. The unvaccinated were hospitalized at a rate 3.7-times higher than the vaccinated and the risk of dying was 10-times higher for the unvaccinated.

“The COVID-19 vaccines are still doing their job by stopping the spread of many new infections, and by preventing severe illness, hospitalization, and death,” said department Secretary Karen Timberlake in a statement. However, because no vaccine is perfect, some breakthrough cases are expected, the health department said.

In February, among those who were vaccinated there were nearly 57 confirmed or probable cases of COVID-19 per 100,000 people in the state. In July, that increased to just over 125 cases per 100,000 vaccinated people, health department data shows.

In February, there were nearly 386 cases per 100,000 people and in July that stood at 369.

In July, the rate of hospitalization for vaccinated people was 4.9 per 100,000 compared with 18.2 per 100,000 for the unvaccinated. And the death rate was 0.1 per 100,000 for the vaccinated and 1.1 per 100,000 for the unvaccinated.

Deaths and hospitalizations are at a level in Wisconsin not seen since February, an uptick health officials blame on the more contagious delta variant. The seven-day average of new cases as of Wednesday was 1,224 and the seven-day average of deaths was six.

As of Thursday, 727 people were hospitalized due to COVID-19, a level not seen since January when the vaccine was not yet widely available, according to the Wisconsin Hospital Association.

Just over 50% of the state’s total population, and nearly 61% of adults, have been fully vaccinated.