Stanislaus County has reported 20 breakthrough cases of COVID-19 in people who were fully vaccinated.
Kamlesh Kaur, a county health services spokesperson, said of the cases, one person was hospitalized. The county Health Services Agency is investigating if the patient was hospitalized due to complications of COVID-19.
State and federal agencies are monitoring for cases of COVID-19 illness in vaccinated people to make sure the vaccines are effective. And thus far the number of confirmed cases is considered encouraging.
Health officials said they expect to identify more post-vaccination cases because the coronavirus vaccines are not 100 percent effective in preventing COVID-19 illness. The often-stated purpose of the vaccines administered by county clinics, pharmacies and health care providers is prevention of serious illness, hospitalization and death.