San Mateo County Health's Street & Field Medicine team works in partnership with community organization Puente to provide vaccinations in Pescadero. (Photo courtesy of Preston Merchant/San Mateo County Health)

As COVID-19 cases increase slightly in San Mateo County, health officials say that getting vaccinated is the best way to protect against the virus, including the contagious delta variant.

During an update to the county’s Board of Supervisors on Tuesday, Srija Srinivasan, deputy chief of San Mateo County Health, said the number of COVID-19 cases and hospitalizations had increased from the numbers reported one week ago.

There were on average 41 new cases per day — calculated with a seven-day lag — for the week ending last Friday, up from an average of 27 cases per day the previous week. Hospitalizations have risen to double digits since last week, with 12 to 16 patients hospitalized each day in the last several days.

“The virus is circulating and because the delta variant is so contagious, this is a concerning time for those who are not fully vaccinated, including those under the age of 12 or those who have a compromised immune system that might not enable vaccination,” Srinivasan said.

While Srinivasan urged people to wear masks in large, indoor settings where vaccination status might be unknown, she said getting vaccinated is the best way to protect against the virus.

Srinivasan said there are only a small percentage of positive COVID-19 cases among people who have been fully vaccinated, similar to national and statewide statistics.

As of July 14, less than 1 percent — 0.069 percent specifically — of fully vaccinated individuals in California have tested positive for COVID-19.

Moreover, Dr. Anand Chabra, San Mateo County Health COVID-19 mass vaccination section chief, said that fully vaccinated people tend not to end up in the hospital and get serious illness.

Vaccinations in San Mateo County continue to rise, albeit slowly.

As of Tuesday, 88 percent of county residents 12 and older have received at least the first dose of the vaccine, with 5,000 residents vaccinated in the past week, Chabra said.

In addition to hosting pop-up vaccination clinics, the county is promoting vaccinations for youth as part of its Youth Vaccine Week.

On Sunday, Youth Vaccine Week will culminate in a youth-led vaccine clinic at the San Mateo Medical Center from 9 a.m. to 6 p.m.

When asked about the possibility of needing a booster vaccine, Chabra said that the Centers for Disease Control and Prevention and the Food and Drug Administration are not recommending boosters at this time.

The CDC, FDA and the National Institutes of Health are “engaged in a science-based, rigorous process to consider whether or when a booster might be necessary,” according to a July 8 statement from the agencies.

San Mateo County’s COVID-19 data and other information is available online at