As the state continues to rack up vaccinations, some Coloradans may find themselves wondering when enough people will have been vaccinated for life to begin returning to some semblance of normal.
“Herd immunity” — a term for when enough people become immune that the spread of a disease becomes unlikely — could happen when around 70% to 80% of people attain immunity to COVID-19.
The exact percentage depends on what’s called the coronavirus’ “reproduction number,” how many people each infected person was likely spreading the virus to, on average, when there was zero immunity. That number is referred to as R0, pronounced “R naught.”
(On the other hand, the “effective reproduction number,” sometimes written “Re,” represents the level of infectiousness once the virus is more common and once public health measures — such as mask-wearing, restrictions on capacity at businesses and so on — are implemented.)
An analysis by the Colorado School of Public Health says if the R0 for COVID-19 was 3 people, herd immunity is estimated to be reached when 66.7% of people are immune. And if R0 was 5, herd immunity would be reached at 80%. The report noted that there is uncertainty regarding the true herd immunity threshold.
State officials are relying on the estimate that herd immunity will be achieved at about 67%, but Colorado is “striving for an even higher number of vaccinations,” said a statement from the Colorado State Joint Information Center, which takes questions for the state public-health department.
The school of public health’s report says its estimates are based on the theory that immunity from a symptomatic COVID-19 infection is assumed to last roughly one year, and immunity from asymptomatic infection is assumed to last about six months.
“This means people who were infected early in the pandemic may no longer be immune to infection unless they have been vaccinated,” the state information center said.
The school of public health’s April 7 report estimates that slightly under 67% of Colorado’s population will be immune to COVID-19 due to vaccination or prior infection by late June. But at that point, the growth in immunity could start to plateau, the report says.
“Initially, demand for the vaccine outweighed the supply, and the Coloradans most interested in being vaccinated were eager to get appointments. Now that we have more vaccine supply, we expect demand to level out as we shift to vaccinating people who are open to getting vaccinated but aren’t in a hurry,” the state information center said. “At the same time, we are working to increase vaccine uptake through outreach and communications and addressing vaccine hesistancies in various populations.”
State officials are a bit more optimistic than the report, remaining “hopeful (that) 70% to 80% of Coloradans will be vaccinated by the end of June,” the information center said.
In a “recent survey we conducted, there was a significant shift in the percent of Coloradans interested in getting vaccinated when one is available, with 88% of Coloradans now indicating they would possibly be vaccinated, up from 66% in September,” the information center said.
Even with Colorado’s six mass vaccination sites around the state up and running — and with local health providers also putting shots in arms — state officials knew they needed to go further to reach Coloradans who can’t drive to appointments or set them up online.
That’s why Colorado started organizing what it calls “equity clinics” — and as of mid-April, state officials had worked with more than 100 community organizations in the effort to reach low-income areas, people of color and rural residents, too.
For some communities, barriers to coronavirus vaccination aren’t just economic but can also stem from distrust, Gov. Jared Polis said.
“It is important that people understand some of the legitimate roots of that skepticism, where, inexcusably, Black Americans were experimented on without their permission,” Polis told Colorado Community Media.
That’s a reference to what became known as the Tuskegee syphilis study: In 1972, the Associated Press broke news that the federal government had let hundreds of Black men in rural Alabama go untreated for syphilis for 40 years for research purposes. A public outcry ensued, and the study ended three months later, according to the AP.
The effects of the study still linger — it’s routinely cited as a reason some Black Americans are reluctant to participate in medical research, or even go to the doctor for routine check-ups, the AP reported.
But other communities also experience “vaccine hesitancy,” and making vaccination quick and easy is crucial for the state to be able reach “herd immunity,” Polis said. That’s a term for when enough people become immune that the spread of COVID-19 becomes unlikely, which could happen when around 70% to 80% of people attain immunity.
“That means reaching people where they are, and protecting any Coloradans protects all Coloradans,” Polis said.
The state’s Vaccine Equity Outreach Team — co-chaired by Jill Hunsaker Ryan, executive director of the state public-health department, and Rick Palacio, strategic consultant to the governor — worked to schedule vaccine equity clinics across Colorado in partnership with community-based organizations, local public health agencies and tribes, according to a news release from the state public-health department.
“One of the data points we use to guide our efforts are targeted census tracts,” Palacio said, using a term for geographic areas. State officials targeted tracts that are below the poverty line and high in minority populations and also worked with organizations that serve those areas.
“Not everyone has a health care home,” and often that includes Black and brown communities, Palacio said.
State officials have partnered with community organizations to host more than 200 clinics across the state, according to Polis’ office.
“They’ve been in church and school parking lots, at local rec centers, and a variety of other locations that community members trust,” said Elizabeth Kosar, a spokeswoman for the governor.
Many of the equity clinics are temporary, and others were ongoing as of late April. Some ongoing locations, according to the governor’s office, include:
• Project Angel Heart, an organization that delivers meals to people with life-threatening illnesses, at 4950 N. Washington St. in Denver.
• Bear Valley Branch Library at 5171 W. Dartmouth Ave. in Denver.
• Village Exchange Center, a nonprofit that serves immigrants and refugees in the Denver metro area, at 1609 N. Havana St in Aurora.
• Fort Lupton recreation center at 203 S. Harrison Ave.
On top of that, a mobile vaccine clinic program is also helping distribute vaccine shots around Colorado. The mobile vaccine clinics kicked off on April 2, and the equity clinics began in January, according to Polis’ office. The state had two bus routes as of late April.
“The mobile vaccine clinics are currently running routes in Northeast and Southern Colorado. Previous stops include Eaton, Sterling, Yuma, Fort Morgan, Avondale, Ordway, La Junta, Las Animas and Lamar,” Kosar said. “And soon, we will be launching a third bus, which will run a route reaching mountain communities.”
Most Coloradans can access vaccines via local pharmacies, hospitals or the state’s mass vaccination sites. Four of the mass vaccination sites now accept walk-ins — Coloradans no longer need an appointment, according to Gov. Jared Polis’ office.
Those four sites are:
• Pueblo County — Colorado State Fairgrounds, 8 a.m. to 6 p.m. Monday through Sunday
• Larimer County — The Ranch Events Complex, 10 a.m. to 6 p.m. Monday through Saturday
• Denver — Ball Arena, 9 a.m. to 7 p.m. Monday through Saturday.
• Mesa County — Grand Junction Convention Center, 9 a.m. to 7 p.m. Wednesday through Saturday.
The other sites will accept same-day registrations if appointments are available and haven’t been filled, Polis’ office said. Those other mass vaccination sites are in Adams County at Dick’s Sporting Goods Park and in El Paso County at the Broadmoor World Arena. Register for those locations here.
Colorado also is served by “mobile vaccine clinics” that travel around the state. Visit mobilevax.us/clinics to sign up and see a schedule of upcoming clinics.
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