LOS ANGELES (CBSLA) — The highly contagious Delta variant has sent COVID-19 infections surging again in Los Angeles County.

Public health officials on Thursday reported 839 new COVID-19 cases, representing a 165% increase from last week. Testing positivity has doubled to 2.5%, and the rate of new daily cases is now 3.47 per 100,000 residents, up from 1.74 last week. Another 11 deaths were also reported.

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Across the state, cases are also up. California’s 7-day positivity rate has climbed steadily since mid-June, and is now at 2.1%. The California Department of Public Health also reported 1,416 newly confirmed cases on Wednesday.

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The recent rise in cases have been fueled by the highly contagious Delta variant, which public health officials say has become the state’s most identified strain of the coronavirus. While there have been some breakthrough infections of people who have vaccinated, most of the new infections have been among the unvaccinated population.

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California has fully vaccinated 50% of its population, but public health officials are concerned that the Delta variant will continue to run rampant through pockets of unvaccinated communities and mutate even further. In Los Angeles County, 60,000 doses are being distributed weekly, way down from the winter/spring peak of about 500,000 per week. At the current pace of vaccinations, Los Angeles County won’t meet its goal of getting 80% of the eligible population 16 and older vaccinated with at least one dose until at least October.