In troubling spike, L.A. County sees 3,000 new coronavirus cases in three days

A microscope image of circular virus cells
This transmission electron microscope image shows SARS-CoV-2, the coronavirus that causes COVID-19.
(National Institute of Allergy and Infectious Diseases Rocky Mountain Laboratories)

Los Angeles County has recorded more than 3,000 new coronavirus cases in three days, part of a troubling rise in cases as viral transmission increases among unvaccinated people.

It was the first time since early March that the county reported three consecutive days with more than 1,000 new coronavirus cases.

The numbers underscore growing concerns about how the highly contagious Delta variant is spreading among unvaccinated people. Officials have said those who have received vaccinations have an excellent chance of being protected.

Of 4.67 million L.A. County residents who have been fully vaccinated, only 0.06% have subsequently tested positive for the coronavirus, 0.004% have been hospitalized for COVID-19, and 0.0004% have died.


Data from Britain cited last week by Dr. Anthony Fauci, the U.S. government’s top infectious-diseases expert, say that the two-dose course of the Pfizer-BioNTech vaccine is 96% effective in preventing hospitalization from COVID-19, 88% effective in preventing symptomatic infection and 79% effective in preventing lab-confirmed infection. Experts believe the Moderna vaccine — because it’s based on the same technology as Pfizer’s — is similarly effective.

Fauci also expressed confidence in the Johnson & Johnson vaccine’s effectiveness. The Johnson & Johnson vaccine uses technology similar to one used in the AstraZeneca vaccine, which studies in Britain show is 92% effective against hospitalization and 60% effective against either symptomatic disease or lab-confirmed infection.

New data demonstrate that vaccines are just as effective in protecting people against the Delta variant as other strains. About 89% of people who tested positive for the Delta variant in L.A. County in June were either unvaccinated or partially vaccinated; that percentage is about the same for the Alpha and Gamma variants and all other strains combined.

Post-vaccination infections among L.A. County cases tested for variants among specimens collected June 2021

Roughly 59% of L.A. County residents are at least partly vaccinated, but that leaves millions who are at risk, officials said.

“We’re a large county, and so the numbers are staggering in terms of people who are at risk of being able to get infected,” Los Angeles County Public Health Director Barbara Ferrer said last week.

On Friday, 1,044 coronavirus cases were reported in Los Angeles County, and an additional 1,069 cases were reported Saturday, according to a Los Angeles Times tally. On Sunday, 1,113 new cases were reported.

For the seven-day period that ended Sunday, L.A. County reported an average of 825 new cases a day. That’s over three times higher than the average number of cases for the seven-day period that ended June 26, when 244 cases were reported a day.


Hospitalizations are rising, too. COVID-19 hospitalizations Friday rose to 373 — the highest number since early May — and up about 76% from the record low set June 12, when hospitalizations fell to 212. On Saturday, L.A. County reported 372 hospitalizations.

The daily number of reported COVID-19 deaths remains low, averaging six a day.

Officials said that it’s unvaccinated younger residents who are transmitting the virus the most. Of the new cases reported Saturday, 70% of them were in adults ages 18 to 49.

“Because of increased intermingling and summer social activities and the circulation of more variants … there is increased risk of COVID-19 infection for people who aren’t fully vaccinated,” the L.A. County Department of Public Health said in a statement.

Average daily coronavirus cases across California are also increasing. By Saturday night, California was reporting an average of more than 2,000 new cases a day over the last week, a figure that hasn’t been seen since April. Statewide hospitalizations climbed to 1,414 as of Saturday, a number that hasn’t been seen since mid-May.

“Our current hospitalization trends & increasing Delta variant … infecting our remaining unvaccinated are concerning,” California state epidemiologist Dr. Erica Pan said in a tweet.

L.A. County continues to recommend that even fully vaccinated people wear masks in indoor public spaces amid some concerns that a very small number of vaccinated people may be able to transmit the virus to other people.

State and federal officials have said there is no need for fully vaccinated people to wear masks in indoor settings, given the high level of effectiveness of the vaccines.

Delta is now California’s most identified variant, accounting for 42.9% of cases analyzed in June, according to figures the state Department of Public Health released Thursday.

The U.S. Centers for Disease Control and Prevention also estimates that the Delta variant, which is believed to be twice as transmissible as conventional coronavirus strains, now makes up 51.7% of cases nationally.