Health care providers in Santa Clara and San Mateo counties are reeling from a massive spike in requests for COVID-19 vaccines last week, after state and county officials greatly expanded eligibility for the vaccine.

The crush of demand starting last week temporarily crashed the Sutter Health website, and residents reported sitting on hold with Kaiser Permanente for three to five hours in an attempt to schedule an appointment. Once someone does pick up, residents reported mixed success — some were able to schedule an appointment, which are now pushed back to February, while others are being turned away due to constraints in vaccine supply.

In a statement Jan. 15, Kaiser apologized for the sluggish and overloaded call system, noting that the state's new eligibility guidelines pose a significant challenge. There are not nearly enough doses to vaccinate all interested residents age 65 and older, and it's difficult to plan ahead when state allocations to health care providers are only revealed on a weekly basis.

As a result, most people who qualify to receive the vaccine will not be able to schedule an appointment at this time, Kaiser said in the statement.

"We sincerely apologize to our members who have encountered long wait times when calling for a vaccination appointment and understand the frustration this causes. We are grateful for everyone's patience and are taking action to alleviate the situation as we work on more ways to increase access to vaccinations as supply allows," according to the statement.

Up until last week, COVID-19 vaccine eligibility in California narrowly focused on health care providers and those living and working in long-term care facilities, including skilled nursing homes. The next "tier" of residents to qualify for the vaccine was supposed to be workers in education, child care, emergency services, food and agriculture.

But Gov. Gavin Newsom announced on Jan. 13 new guidelines in which all residents age 65 and older will now qualify for the vaccine, abruptly extending eligibility to more than 3 million additional Californians.

Santa Clara County officials were quick to announce more modest guidelines for local residents, extending its vaccine supply to people age 75 and older and noting that there won't be enough doses available to accommodate the state's ambitious guidelines.

San Mateo County remained focused on vaccinating health care workers in its first phase of vaccine rollout. On Jan. 17, county officials said that it is transitioning to the next vaccination phase, which now includes residents 65 and older "as the supply of vaccines allows" but as of Jan. 19, did not have enough vaccine to actually do so. Residents are encouraged to check with their private health care providers to confirm if they are vaccinating people 65 and over, but should not expect to get access through county-run vaccination clinics yet.

Many private health care providers, including Sutter Health and Stanford Health Care, have followed in Santa Clara County's footsteps and are providing appointments to people age 75 and older. Kaiser opted to follow the state guidelines and immediately reached out to patients who are 65 and older, leading to call volumes and wait times that "remain extremely high."

Kaiser has since increased staffing in its call center and now operates it 24 hours a day, and is telling callers up front if there are no more available appointments for that day. The hope is that by this week, Kaiser patients will be able to schedule vaccine appointments solely through its website.

Another cause for concern is whether there will be enough COVID-19 vaccine supply to provide second doses. Residents receiving the vaccine developed by Pfizer must receive two doses of the vaccine 21 days apart, while those receiving the Moderna vaccine must receive two doses 28 days apart.

State and local officials were reassured that there was a federal stockpile of "second dose" vaccinations, and told not to sit on reserves that could be otherwise used to vaccinate more people.

Last Friday, it was revealed that the federal government may have secretly depleted that stockpile of vaccines. Santa Clara County officials blamed former President Donald Trump's administration for the poor communication, and are unsure what it will mean for the expanded rollout of the COVID-19 vaccine.

Anyone interested in getting the vaccine can go to the following:

Kaiser Permanente

Residents age 65 and older qualify for the vaccine. Information and scheduling for appointments can be found at mydoctor.kaiserpermanente.org or by calling 866-454-8855. Kaiser's website is now advising people age 75 and older not to call or email, and to await a letter or email about available appointments.

Sutter Health/Palo Alto Medical Foundation

Residents age 75 and older qualify for the vaccine. Appointments can be scheduled at sutterhealth.org or by calling 844-987-6115. Patients are asked not to call their care site or provider's office for vaccination scheduling, and to expect long wait times.

Stanford Health Care

Residents age 75 and older qualify for the vaccine. Appointments can be scheduled at stanfordhealthcare.org or by calling 650-498-9000. Vaccinations for people age 65 and older were expected to start Jan. 20.

Santa Clara County Medical Center Hospitals and clinics

Residents age 75 and older qualify for the vaccine. Eligibility restricted to those who receive primary care through the county health system and do not receive care from Kaiser, Sutter or Stanford. Appointments can be made at sccfreevax.org, which has a link to the sign-up form.

El Camino Health

Residents age 75 and older qualify for the vaccine. Eligibility is restricted to those who do not receive primary care from the Santa Clara County health system, Kaiser, Sutter or Stanford. Appointments can be made at elcaminohealth.org. A phone number is not available.