COVID-19 weekly update: Cases increase by 18,135 as 30% of weekly tests return positive

COVID-19 cases in Arizona continue to rise because of highly contagious subvariants, and a higher percentage of tests came back positive than seen since January, according to the state's weekly update.

On Wednesday, health officials added 18,135 new COVID-19 cases and 66 new known deaths over the weeklong period ending July 16. June and July have seen relatively similar weekly case additions, with this past week's slightly higher.

Case counts are still far below the winter, state data shows. Case numbers in recent months likely are not showing the full picture of infections as many more people have used at-home test kits and may not report positive results to county health departments.

Arizona like other states is seeing an ongoing case increase now largely driven by two contagious subvariants of the virus, BA.4 and BA.5, with BA.5 the more dominant of the two. It's also likely contributing to reinfections given its contagiousness and ability to evade antibodies.

Learn more: 'It is spreading everywhere': What to know about the latest COVID-19 wave in Arizona

Residents in 10 of Arizona’s 15 counties, including Maricopa County, should be wearing face masks indoors in public because of COVID-19 levels, according to guidance from the Centers for Disease Control and Prevention as of Thursday.

The CDC’s “community level” guidance is updated weekly and ranks counties as low, medium and high, or green, yellow and orange. The Arizona counties designated as “high,” where masks are recommended, are Maricopa, Pinal, Apache, Coconino, Gila, La Paz, Mohave, Navajo, Yavapai and Yuma. Greenlee, Santa Cruz, Pima, Graham and Cochise were “medium,” and no counties were “low” as of Thursday.

The metrics are based on a county’s COVID-19 hospital bed use, COVID-19 hospital admissions and case rates for the virus over the past week.

Reported cases since the pandemic began are approaching 2.2 million. Known deaths in Arizona are at about 30,700.

Wednesday marked the 21st of the weekly updates to the state's data dashboard, instead of daily updates that Arizonans became accustomed to following for the latest data on infections, illnesses and deaths.

The previous week's update added 15,280 cases and 60 deaths, compared with 20,198 cases (high because old cases were added) and 57 deaths, 16,514 cases and 63 deaths, 15,373 cases and 52 deaths, 16,334 cases and 28 deaths, 14,677 cases and 40 deaths, 13,042 cases and 33 deaths, 11,498 cases and 40 deaths, 7,204 cases and 29 deaths, 5,490 cases and 41 deaths, 3,911 cases and 238 deaths, 2,350 cases and 99 deaths, 2,377 cases and 29 deaths (low because of a processing error), 2,777 cases and 142 deaths, 6,840 cases and 413 deaths, 10,143 cases (high because of a reporting catch-up) and 385 deaths, 4,566 cases and 336 deaths, 5,153 cases and 457 deaths, 6,549 cases and 382 deaths and 9,647 cases and 449 deaths the 19 weeks prior.

This week's update shows the differences between data reported for the week of July 10-16 and July 3-9.

Health officials say weekly updates match how public health monitors trends and other disease reporting.

Case numbers generally were relatively lower in the past couple of months, and public health experts estimate cases of the highly contagious omicron variant peaked in Arizona around mid-January.

The state data dashboard no longer shows key hospitalization information since Gov. Doug Ducey ended the COVID-19 emergency declaration on March 30. State health officials said hospitals are no longer required to report some COVID-19 surveillance data to the state, meaning certain graphs showing weekly hospitalization levels for the disease and bed usage by COVID-19 patients are no longer updated.

At the time that data reporting stopped, hospitalizations for the disease had dropped steadily since late January.

The CDC still reports state hospitalization data for Arizona and showed a 15.3% increase in the seven-day average of COVID-19 hospital admissions during July 11-17 compared with July 4-10. Hospital admissions last week were down 78.8% from the peak seven-day average in early January 2021.

The number of known deaths in the state was at 30,698 as of Wednesday, after passing 30,000 known deaths in the May 4 update, 29,000 deaths in the March 30 update, 28,000 deaths in the March 9 update, 27,000 deaths on Feb. 10 and 26,000 deaths on Jan. 28. The state surpassed 25,000 deaths on Jan. 13. Deaths are now reported with a four-week lag.

Arizona's overall pandemic death rate since early 2020 is the third-highest nationwide.

State data on breakthrough infections

The state in December began publicly disclosing data on breakthrough COVID-19 infections, and state officials say the data underscores the effectiveness of the vaccine — especially for people with booster doses.

Data from May show that 25.6% of cases, 24.9% of hospitalizations and 19.2% of COVID-19 deaths were among fully vaccinated people without a booster, with much of the rest among unvaccinated people. Fully vaccinated people with a booster made up 36.4% of reported cases, 31.5% of hospitalizations and 26% of deaths in May.

The COVID-19 virus' disproportionate impact on older adults, who are also more likely to have a booster dose, could help explain why a higher percentage of people who were fully vaccinated and boosted died of COVID-19 in April than those who were fully vaccinated and not boosted. The effectiveness of boosters also appears to wane after several months. But the precise explanation for those percentages of deaths is unclear.

Looking at the proportions of deaths by vaccination status does not tell the risk, though. State health officials recommend considering the rates of death among boosted individuals versus unvaccinated individuals, which show significantly lower death rates in vaccinated and boosted individuals compared with unvaccinated individuals.

Health officials emphasize the best protection against severe illness from COVID-19 is to remain up to date with recommended vaccinations, including second booster doses for those 50 and older and people who are immunocompromised.

Unvaccinated people 12 and older in Arizona had a 1.8 times greater risk of testing positive for COVID-19, 8 times greater risk of hospitalization from COVID-19 and 21 times greater risk of dying from COVID-19 in May compared with fully vaccinated people with a booster, according to a state analysis.

Unvaccinated people had a 3.4 times greater risk of testing positive, 6.6 times greater risk of hospitalization and 15 times greater risk of dying from COVID-19 compared with individuals who were fully vaccinated without a booster.

As of July 13, there had been 2,057 breakthrough deaths in fully vaccinated individuals, according to state health officials’ preliminary data, which works out to a breakthrough death rate of about 0.04% among fully vaccinated people.

Case rates and death reports

Contagious omicron subvariants, particularly BA.5, are contributing to many of the cases in Arizona, according to results from sequencing labs.

Percent positivity, which refers to the percentage of COVID-19 diagnostic tests that are positive, varies somewhat based on how it's measured. It was high in the winter months, a sign of more community spread. Then it was much lower but has been climbing upward since April.

For most of December, Arizona's percent positivity for COVID-19 testing was at 11%-13%, before rising to 22% for the week of Dec. 26, 29% for the week of Jan. 2, 32% for the week of Jan. 9, 34% for the week of Jan. 16, 29% for the week of Jan. 23, 22% for the week of Jan. 30, 16% for the week of Feb. 6, 11% for the week of Feb. 13, 7% for the week of Feb. 20, 4% for the week of Feb. 27, 3% for the week of March 6, 3% for the week of March 13, 3% for the week of March 20, 3% for the week of March 27, 3% for the week of April 3, 4% for the week of April 10, 5% for the week of April 17, 6% for the week of April 24, 8% for the week of May 1, 11% for the week of May 8, 15% for the week of May 15, 18% for the week of May 22, 21% for the week of May 29, 22% for the week of June 5, 23% for the week of June 12, 27% for the week of June 19, 27% for the week of June 26, 28% for the week of July 3 and 30% for the week of July 10. The percentages are now for all diagnostic tests conducted, rather than for unique individuals tested, following a change to the state dashboard.

A positivity rate of 5% or less is considered a good benchmark that the disease's spread is under control.

The state's overall COVID-19 death and case rates since Jan. 21, 2020, still remain among the worst in the country.

The COVID-19 death rate in Arizona since the pandemic began is 420 deaths per 100,000 people as of Tuesday, according to the CDC, putting it third in the country in a state ranking that separates New York City from New York state. The U.S. average is 307 deaths per 100,000 people as of Tuesday, according to the CDC.

New York City has the highest death rate, at 487 deaths per 100,000 people, followed by Mississippi at 422.

Arizona's first known death from the disease occurred in mid-March 2020.

Many of the reported deaths occurred days or weeks before because of reporting delays and death certificate matching.

A total of 2,179,180 COVID-19 cases were identified across the state through July 16.

Vaccination update

Arizonans ages 6 months and older are eligible for the Pfizer vaccine, while the Moderna vaccine is approved for children ages 6 months to 5 years and people 18 and older. The CDC has recommended the Johnson & Johnson vaccine on a more limited basis for people 18 and older. Many individuals are eligible for booster doses, too.

The state reported over 5.2 million people in Arizona — about 73.1% of the total state population — had received at least one vaccine dose through July 15, with nearly 4.5 million residents fully vaccinated against COVID-19. The state’s data dashboard now separates out doses administered to Arizona residents versus all doses administered in the state.

Arizona's rate of fully vaccinated people out of the total population was 62.5%, which was behind the national rate of 67.1%, according to the CDC as of July 13.

Out of people ages 5 and older, 66.5% of those in Arizona were fully vaccinated, compared with 71.3% at the national level, CDC data shows.

Health experts strongly recommend booster shots for those eligible, especially with the omicron variant spreading. About 47.3% of fully vaccinated Arizonans over the age of 18 had received a first booster shot as of July 6, below the national rate of 51.3% for that same age group.

What to know about latest numbers

Reported cases in Arizona: 2,179,180, as of July 16.

Cases by county: 1,374,075 in Maricopa; 276,269 in Pima; 141,197 in Pinal; 65,241 in Yuma; 61,459 in Mohave; 52,348 in Yavapai; 47,790 in Coconino; 41,686 in Navajo; 34,266 in Cochise; 28,502 in Apache; 18,412 in Gila; 17,512 in Santa Cruz; 12,531 in Graham; 5,545 in La Paz; and 2,347 in Greenlee, according to state numbers.

The rate of cases per 100,000 people since the pandemic began is highest in Apache County, followed by Navajo, Gila, Santa Cruz, Graham and Coconino counties, according to state data. The rate in Apache County is 39,692 cases per 100,000 people. By comparison, the U.S. average rate since the pandemic began is 26,948 cases per 100,000 people as of Tuesday, according to the CDC.

The Navajo Nation reported 59,229 cases and 1,842 confirmed deaths as of Tuesday. The Navajo Nation includes parts of Arizona, New Mexico and Utah.

The Arizona Department of Corrections reported 15,210 inmates had tested positive for COVID-19 as of Tuesday, including 2,471 in Tucson, 2,279 in Eyman, 2,240 in Yuma, 1,782 in Lewis and 1,436 in Phoenix; 57,229 inmates statewide have been tested. A total of 5,340 prison staff members have self-reported testing positive, the department said. Sixty-two incarcerated people in Arizona are confirmed to have died of COVID-19, with 16 additional deaths under investigation.

The race/ethnicity breakdown of cases since the start of the pandemic in 2020 is 40% white, 29% Hispanic or Latino, 5% American Indian, 4% Black and 2% Asian/Pacific Islander. Race/ethnicity of positive cases since the onset of the pandemic is unknown in 14% of cases and listed as other race in 6% of cases.

Of those who have tested positive in Arizona since the start of the pandemic, about 21% were younger than 20, 42% were 20-44, 13% were 45-54, 11% were 55-64 and 12% were age 65 or older.

Laboratories had completed 20,213,642 total diagnostic tests for COVID-19 as of July 16, 12.4% of which have come back positive. That number includes both PCR and antigen testing.

Percent positivity was at 30% for the week of July 10, the highest it's been since January. The state numbers leave out data from labs that do not report electronically.

The state Health Department includes probable cases as anyone with a positive antigen test, another type of test to determine infection. Antigen tests (not related to antibody tests) use a nasal swab or another fluid sample to test for current infection. Results are typically produced within 15 minutes.

A positive antigen test result is considered very accurate, but there's an increased chance of false-negative results, Mayo Clinic officials said. They say a doctor may recommend a PCR (polymerase chain reaction) test to confirm a negative antigen test result.

Arizona as of Tuesday had the 14th highest overall case rate in the country since Jan. 21, 2020. Ahead of Arizona in cases per 100,000 people since the pandemic began are Rhode Island, Alaska, North Dakota, Kentucky, Guam, New York City, Tennessee, Utah, Florida, South Carolina, West Virginia, Wisconsin and Delaware, according to the CDC.

Arizona's infection rate is 29,690 cases per 100,000 people, according to the CDC. The national average is 26,948 cases per 100,000 people, although the rates in states hard hit early in the pandemic may be an undercount because of a lack of available testing in March and April 2020.

Reported deaths in Arizona: 30,698

Deaths by county: 17,579 in Maricopa; 3,919 in Pima; 1,688 in Pinal; 1,490 in Mohave; 1,245 in Yavapai; 1,189 in Yuma; 917 in Navajo; 619 in Apache; 583 in Cochise; 484 in Coconino; 387 in Gila; 232 in Santa Cruz; 180 in Graham; 147 in La Paz; and 39 in Greenlee.

People age 65 and older make up 21,827 of the 30,698 deaths, or 71%. About 16% of deaths were among people 55-64 years old, 8% were 45-54 and 5% were 20-44 years old.

While race/ethnicity was unknown for 4% of deaths, 56% of those who died were white, 26% were Hispanic or Latino, 7% were Native American, 3% were Black and 1% were Asian/Pacific Islander, the state data shows.

The global death toll as of Wednesday was 6,378,708. The U.S. had the highest death count of any country in the world, at 1,024,951, followed by Brazil at 675,871 and India at 528,388, according to Johns Hopkins University.

Arizona's 30,698 deaths represent about 3% of COVID-19 deaths in the United States.

Republic reporter Stephanie Innes contributed to this article.

Reach the reporter at Alison.Steinbach@arizonarepublic.com or at 602-444-4282. Follow her on Twitter @alisteinbach.

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This article originally appeared on Arizona Republic: Arizona weekly COVID-19 update adds 18,135 cases, 66 deaths