Here’s how many Sacramento residents are past due on their second dose of COVID vaccine
A little more than one in 20 recipients of first doses of the Pfizer or Moderna COVID-19 vaccine in Sacramento County have either skipped out on or are overdue for their second dose, according to figures released by the local health office.
The county broke down timing status for close to 538,000 recipients of either of the two vaccines, which each require two doses spaced weeks apart.
Of them, about 28,400 — 5.3% — had reportedly not received their second dose and were more than six weeks beyond their first dose date, according to data shared Thursday by Sacramento County’s public health office.
About 363,000 of the 538,000 recipients tallied through April 23 were marked as having their regimen “complete,” while the remaining 175,000 were “incomplete” because both doses had not yet been received. The 28,400 past due were a subset of the latter group.
The manufacturers’ recommended timelines between doses are three weeks for Pfizer and four weeks for Moderna, but state and federal health guidelines indicate the two doses of either vaccine can come up to six weeks apart without losing effectiveness.
The U.S. Centers for Disease Control and Prevention recently put out information indicating about 8% of first-dose recipients did not receive their second dose, which was widely reported by national news outlets. This was up from about 3.4% in a CDC report released in March.
However, as those outlets also reported and the March report clarified, both percentages were based on canceled or missed appointments according to providers, not accounting for those who may have gotten their first dose from one provider and their second dose from a different provider.
The recent numbers from Sacramento classify the recipients by county of residence rather than breaking down doses by provider, meaning they should not face this discrepancy.
“We’ll analyze it further and provide additional information,” county health officer Dr. Olivia Kasirye said on a Thursday morning teleconference with reporters.
The local data also showed that about four out of five residents who received either vaccine got their second dose at the recommended 21- or 28-day interval: 80% of Pfizer recipients and 79% of Moderna recipients who completed both doses got their second dose right on time, the numbers show.
Nearly all of the remaining 20% of the “completed” group came back outside the manufacturer recommended-timeline but within the allowed six-week window; just a fraction of a percent for each brand, at 0.4% for Moderna and 0.2% for Pfizer, got their second shot more than six weeks after their first.
Early clinical data have suggested people do receive some level of baseline protection against COVID-19 after a single dose of Pfizer or Moderna, which both use mRNA technology.
But federal health officials say it is imperative to receive both doses to develop necessary antibodies for long-term protection.
“There is currently limited information on the effectiveness of receiving your second shot earlier than recommended or later than 6 weeks after the first shot,” CDC guidance says.
Because of this uncertainty, it’s still largely unclear to what extent so-called second-dose skippers may pose a problem in the long term. This could also depend on how supply and usage of the Johnson & Johnson vaccine develop in the coming months, since J&J requires only one dose.
Pfizer and Moderna combine for more than 90% of California’s more than 12 million fully vaccinated residents, according to data from the California Department of Public Health updated Thursday, with fewer than 1.1 million from J&J.
Experts have said the threshold required to reach herd immunity — the point at which enough of the population is protected via vaccine or natural immunity that it protects against spread even among the non-immune — has been estimated at anywhere from around 70% to 85% or higher for COVID-19. State and local health officials including Kasirye have referenced 70% as a low-end goal for vaccination rate.
This could mean that even a relatively small figure like 5% of two-dose recipients either not being fully protected or having their vaccine protection wear off early could potentially hinder herd immunity progress, particularly if a community’s vaccine uptake rate puts it near the low end of the anticipated herd immunity range.
There are additional incentives outside of direct health benefits prompting people to get both their doses.
As the economy reopens, some events and venues are opening attendance only to those who are considered fully vaccinated — two weeks past their final dose — or who can show proof of a negative COVID-19 test.
Golden 1 Center in Sacramento, for example, has opened limited attendance at Kings home games only to these groups.
This story was originally published April 30, 2021 at 10:53 AM.
