Vaccines Continue to Provide Powerful Protection Against the Delta Variant

LOS ANGELES, July 29 – The Los Angeles County Department of Public Health (Public Health) is reporting 3,248 new cases of COVID-19, a 17% increase over last week. The daily average case rate is now 15.7 cases per 100,000 people, an increase of 21.7% from last week’s rate of 12.9 cases per 100,000 people. This is a significantly smaller rate of increase than seen last week, where cases increased over 80% from the prior week.

Over the last few weeks, case rates have risen precipitously among unvaccinated people. In June, 80% of all new cases were among those not vaccinated. While cases are also rising among vaccinated people, this increase is smaller and slower than it is in unvaccinated people. Between May 1 and July 17 of this year, our county had 3,167 hospitalized COVID cases: 92% were among unvaccinated or partially vaccinated individuals, and 8%, were among those fully vaccinated. These trends contribute the certainty that the vaccines are working as intended: although vaccinated people are seeing a rise in new COVID diagnoses, they are primarily experiencing their infections not as severe illnesses that bring them to the emergency room, but as bad colds. As the data shows, unvaccinated people simply cannot have the same level of confidence that an infection with this virus will lead to mild illness.

To date, Public Health has identified 1,293,450 positive cases of COVID-19 across all areas of L.A. County and a total of 24,675 deaths. Of the 17 new deaths reported today, four people that passed away were over the age of 80, three people that passed away were between the ages of 65 and 79 years old, and 10 people who passed away were between the ages of 50 and 64 years old.

Testing results are available for nearly 7,300,000 individuals with 16% of people testing positive. Today’s daily test positivity rate is 5.17%, an increase of less than half a percentage point (0.44) from last week’s rate of 4.73%, which was itself an increase of nearly a full percentage point over the previous week. This also suggests that our rate of increase may be stabilizing.

Specimens sequenced by several labs serving Southern California, including the L.A. County Public Health lab show the Delta variant is on the rise. Sequences collected between July 18 and 24 show that the Delta variant was isolated in 96% of the 675 specimens sequenced that week. This is consistent with the rise of Delta nationwide and CDC estimates. Given nearly 4 million residents in L.A. County are not yet vaccinated, risk of increased spread of this variant within our County remains extremely high. This now-predominant strain is more efficiently transmitted between people, likely due to its faster replication, higher viral load, and greater affinity for lower respiratory tract cells compared with earlier COVID strains.

With high rates of transmission in the county, Public Health remains focused on mitigation strategies to reduce the spread of the virus. The most powerful tool we have for lowering viral transmission remains vaccinations. There is ample data and science that prove the vaccines are both safe and effective at preventing serious illness and death.

“For all of those in our County who have lost a loved one to COVID-19, we extend our deepest condolences to you and your family,” said Barbara Ferrer, PhD, MPH, MEd, Director of Public Health. “Vaccinations are critically important to reducing the impact of rising infection on our residents. The science on this variant shows that it is different from earlier variants of COVID: it replicates faster and more efficiently in respiratory tract cells, which means that infected people may now spread up to 1,000 times more virus particles with every cough, sneeze, or shout than they did a year ago. They may also spread the virus efficiently 2 days earlier in their illness course than did people who were infected a year ago. A more infectious variant indicates infected people have more opportunities to transmit the virus and can do so more efficiently before they realize they were even exposed. And while vaccinated people are extremely unlikely to get severely ill from COVID, there is a small risk of getting infected, and transmitting the virus. This is why we are asking everyone to wear a mask indoors, regardless of vaccination status.”

Increased circulation of the highly transmissible Delta variant is leading to case increases across all racial and ethnic groups. In keeping with recent trends, over the month preceding July 17, all groups saw an increase in cases, with the highest case rate observed among Black residents, whose case rate rose from 43 cases per 100,000 people to 181 cases per 100,000 people, an increase of 320%. There were also significant increases in case rates for all groups, with increases of 182% in Latinx residents, 361% in White residents, and 371% in Asian residents. The more recent case incidence rate in Black residents is more than twice that in White residents, and also important to note that now White residents, who have traditionally experienced lower case rates than Latinx and Black residents, are the group with the next highest case rate.

Over the same interval, hospitalization rates have been trending upward by 35 to 90% in Black, Latinx, and Asian residents, and we have seen deaths begin to trend upward among Black, Latinx, White and Asian residents by 71%.