The mass vaccination site at the Oakland Coliseum stopped taking appointments for first shots of the Pfizer vaccine last week as it prepares to switch over to administering only the single-dose Johnson & Johnson vaccine.

The governor’s office of emergency services (Cal OES), which is running the Coliseum site alongside FEMA, tells KRON4 that they stopped giving first doses more than a week ago. Alameda County officials stress that people can still get first doses of the Pfizer vaccine elsewhere in in the county, but for the next three weeks the Coliseum site is only offering second-dose shots.

The site is concentrating on making sure that everyone who got a first dose gets their second within three to six weeks, which is the recommended window.

"Just want to make sure we’re pushing and pushing people to really ensure that they do get that second dose," said FEMA representative Angela Byrd, speaking to KRON4.

Similarly, the Sutter Health appointment system was only allowing second-dose appointments to be made this week — however the healthcare network said this was due to supply issues.

In the last week, health officials have been stressing the efficacy of the Johnson & Johnson vaccine, which members of the public have been wary of after its Phase 3 trials found it to be slightly less effective than the two-dose Pfizer and Moderna vaccines. State Health Officer Dr. Tomas Aragon was at the Oakland Coliseum to get his Johnson & Johnson shot earlier this week, and San Francisco Mayor London Breed also got the single-dose vaccine at a site in the Western Addition on Tuesday.

Experts say the Johnson & Johnson vaccine is nearly 100% effective at preventing hospitalization and death from COVID-19, and if it were put to a real-world trial against the other two vaccines — something that was not done due to the emergency nature of the pandemic — all three may be found to be more or less just as effective as each other. Also, rather than waiting 30 to 40 days for full immunity, the Johnson & Johnson shot confers immunity after just ten days.

The Johnson & Johnson shot is also believed to be 72% effective at preventing people from becoming asymptomatic carriers of COVID-19, it seems to come with fewer side effects and reactions, and it is overall more effective than most flu vaccines.

The Coliseum site will begin giving out only the Johnson & Johnson vaccine on April 5. The original agreement between FEMA and Cal OES had FEMA only staying on site until April 12, but the timeline may get extended.

If you're eligible for a vaccine and looking for an appointment at the Coliseum or other sites in the county, start checking the site early each morning.

Top image: The Coliseum site being set up on February 12. Photo by Justin Sullivan/Getty Images