Stomach Virus Surges Amid Vaccine Drop

Bay Area wastewater monitors are picking up high rotavirus levels in San Jose, Fremont, Redwood City and Marin County, with moderate levels in San Francisco, Sunnyvale and Novato. (nbcbayarea.com) Rotavirus is a stomach virus that spreads when tiny amounts of infected stool contaminate hands, food, toys or surfaces. It can cause diarrhea, vomiting, fever and stomach pain, and young children face the highest risk of severe dehydration. (cdc.gov) (nbcbayarea.com) Norovirus is also circulating in California, but it is a different virus and there is no vaccine for it. California’s public health department says norovirus illness usually starts 12 to 48 hours after exposure, lasts 1 to 3 days, and spreads fast in schools, camps, nursing homes and other shared settings. (cdph.ca.gov) The vaccine piece in this story points to rotavirus, not norovirus. The Centers for Disease Control and Prevention says rotavirus vaccine is given by mouth in 2 or 3 doses during infancy, and the vaccine prevents an estimated 40,000 to 50,000 hospitalizations among U.S. infants and young children each year. (cdc.gov 1) (cdc.gov 2) Coverage has never matched other routine childhood shots. The Centers for Disease Control and Prevention said in August 2024 that routine rotavirus vaccination rose from 65% to 71% among U.S. children born in 2011 through 2020, still below coverage for many other infant vaccines. (cdc.gov 1) (cdc.gov 2) California’s broader school-vaccine picture is mixed. The Public Policy Institute of California reported on April 2 that 93.7% of California kindergartners had all required vaccines in 2024-25, but 12 of 58 counties were below 90% overall and 15 counties were below 95% for measles, mumps and rubella coverage. (ppic.org) Those statewide school figures do not track rotavirus directly, because California’s school-entry rules cover shots such as measles, polio and varicella, while rotavirus is an infant vaccine given before kindergarten. The California Department of Public Health says school and child care requirements remained unchanged in 2025, and its school immunization pages do not list rotavirus among the required entry vaccines. (cdph.ca.gov) Doctors in San Francisco say the current wave is showing up alongside other viruses. SFGATE reported April 20 that WastewaterSCAN data showed high local levels of rotavirus, norovirus, influenza A and B, respiratory syncytial virus, and human metapneumovirus in the Bay Area. (sfgate.com) Rotavirus used to infect nearly every child before age 5 in the pre-vaccine era, and UCSF child care guidance still cites about 50,000 U.S. hospitalizations a year. In children who get sick, fever and vomiting often ease after about two days, but diarrhea can last five to seven days or longer. (cdc.gov) (ucsf.edu) For parents and schools, the practical distinction is simple: rotavirus has a childhood vaccine and is hitting some Bay Area wastewater systems hard, while norovirus has no vaccine and keeps spreading through contaminated hands, food and surfaces. Both viruses can empty a classroom or household fast once vomiting and diarrhea start. (nbcbayarea.com) (cdph.ca.gov)