Alameda County — After a months-long decline in COVID-19 case rates in Alameda County, mounting evidence shows that the so-called Delta variant appears to be playing a key role in a recent surge.

In response, a coalition of eight Bay Area health officers issued a recommendation on Friday, July 16, that all people wear a face mask when indoors, regardless of their vaccination status.

“The Delta variant is spreading quickly, and everyone should take action to protect themselves and others against this potentially deadly virus,” said Alameda County Health Officer Dr. Nicholas Moss. “For masks to work properly, they need to completely cover your nose and mouth and fit snugly against the sides of your face and around your nose.”

It was just over a month ago that the state chucked its COVID-19-related restrictions, collectively known as the Blueprint for a Safer Economy. With a few exceptions, fully vaccinated individuals could refrain from wearing a mask indoors in most everyday situations as of June 15. Almost immediately, downward trends in the metrics that measure the spread of COVID-19 began to reverse themselves.

Alameda County data reported on the state’s website shows a daily case rate as of July 11 was 8.2 per 100,000 residents, and it continues to rise. By comparison, the case rate was 1.7 on June 1. Under the Blueprint for a Safer Economy, a case rate of 7.0 would have pushed the county into the most restrictive purple tier.

Hospitalizations have risen 86% since the end of June, with 114 patients hospitalized for COVID-19 in the county on July 16. And over the course of the month, the test positivity rate has increased steadily from 1.8% to 4.7% as of July 17.

Neetu Balram, public information manager with the Alameda County Public Health Department said in an email to The Independent that most new COVID-19 infections are in unvaccinated residents. To date, 70.4% of county residents over 12 have been fully vaccinated, and 82.9% have been partially vaccinated.

“Vaccines remain the best protection against COVID-19, including the highly infectious Delta variant. Unvaccinated Californians are not only at much higher risk of getting COVID-19 than those who are fully vaccinated, but they are also far more likely to suffer severe illness, hospitalization and death,” said the California Department of Public Health (CDPH) in a statement sent to The Independent. “As we continue to see the real and aggressive impact of the Delta variant in rising case rates, we cannot stress enough how critical it is for eligible individuals to get vaccinated.”

Viruses are constantly mutating, and most mutations of SARS-CoV-2 – the virus that causes COVID-19 – have nominal impact. However, several variants have caused concern among health officials worldwide. The Centers for Disease Control (CDC) classifies variants as either of interest, concern or high consequence. While the CDC reports there are no variants of high consequence, there are four strains – the Alpha, Beta, Delta and Gamma variants – identified as variants of concern.

The Delta variant was first identified in India in December 2020, and it was soon the dominant variant in India and England. In June, it accounted for 49% of infections in California. Information regarding its specific impact in Alameda County was not available.

“As of July 9, there have been 104 Delta-variant cases reported among Alameda County residents,” Balram said. “Genetic sequence information on cases is limited, and no conclusions about local epidemiology should be made from this data.”

Increased transmissibility is a primary concern with the Delta variant. Reports indicate that the Alpha variant is 50% more transmissible than the original SARS-CoV-2 strain; the Delta variant is 50% more transmissible than the Alpha variant. With its significantly increased ease of transmission, the relaxation of COVID-19 restrictions including masking and a plateauing of vaccinations, health officials and others are concerned about the coming months. Worldwide financial markets slumped on Monday, July 19, with the Dow Jones Industrial Average dropping more than 700 points. Analysts put the blame squarely on concerns over the Delta variant and the likely impacts of another surge in COVID-19 cases.

"We are closely monitoring the spread of COVID-19 and its variants across our state,” said Dr. Tomás Aragón, CDPH director and state public health officer, earlier this month. “COVID-19 has not gone away. If you are not vaccinated, you are still at risk. Currently, the Delta variant accounts for approximately 36% of cases sampled in California, and we expect this to rise.”

As Aragón predicted, the impact of the Delta variant has grown since his earlier statement. It now accounts for 58% of all COVID-19 infections in the U.S. and 63% of infections in the region that includes California.

“After vaccination, masking is the next most powerful tool we have to protect ourselves and each other during this latest wave of infections,” Moss said. “Wearing masks, especially indoors and in crowded outdoor settings, will help us contain this more transmissible variant.”