Thousands in Iowa fail to receive second COVID-19 shot

Nearly a quarter of individuals who initiated the COVID-19 vaccine series in Iowa have missed their second dose, according to state public health officials, potentially throwing a wrench in the race toward herd immunity.

More than 66,000 people have skipped or delayed the second shot in a two-dose vaccine series as of May 2, according to data obtained from the Iowa Department of Human Services. Of the 275,013 individuals who have received the first shot of the series, 66,490 have not received a second shot within the recommended time frame, data shows.

The minimum interval between doses for the Pfizer-BioNTech vaccine is 21 days. For Moderna, it’s 28 days.

Of the more than 66,000 individuals, 27,015 are between one and seven days past the minimum interval, said Iowa Department of Public Health spokeswoman Sarah Ekstrand.

More than 1,069,010 Iowans are fully vaccinated as of Tuesday, making up nearly 34 percent of the state’s population, according to state coronavirus data.

Without full protection from the vaccine, the virus still has the ability to spread, which could have serious implications for the state’s effort to reach herd immunity, said Dr. Pat Winokur, infectious disease specialist at the University of Iowa Hospitals and Clinics.

“Skipping the second dose will make it more challenging to control infection in the community simply because there will be more breakthrough cases of infection,” she said.

As of April 26, 61,773 individuals had missed their second dose, state data shows. Of that, 23,104 were a week or less beyond the recommended minimum interval.

State officials did not elaborate on why Iowans may not be returning for their second dose. While state public health officials have raised the alarm in recent weeks about the rate of vaccine hesitancy among Iowans, other public health agencies have said barriers to accessing the shot also are a major driver.

Winokur pointed out it’s a common issue with multi-dose vaccines to have to encourage individuals to return for a second dose. Oftentimes, it’s because people get busy in their day-to-day activities and forget about the second shot, she said.

For others, they may be worried about missing work or school because of symptoms from the vaccine, Winokur said.

The U.S. Centers for Disease Control and Prevention emphasizes it’s essential for individuals to get the second dose as close to the recommended interval as possible.

If that's not feasible, the CDC says individuals can receive the second dose of the Pfizer and Moderna vaccines up to six weeks, or 42 days, after the first dose.

“Even if they are late for getting their second dose, they should get it when they can,” Winokur said. “The second dose is really important and even delivered late it will really improve the immune response to SARS-CoV-2.”

While the number of Iowans only receiving partial immunization could be worrisome, studies have shown a single dose still can be highly effective.

One dose of Pfizer’s and Moderna’s COVID-19 vaccine was found to be 80 percent effective in preventing infections, according to a CDC study published in late March. That study analyzed the effectiveness of the vaccines among nearly 4,000 front-line and other essential workers.

However, the vaccine’s effectiveness reached 90 percent with two doses, the study found.

“One dose will provide some immunity, but the protection will likely not last as long and one dose will not be as effective as two doses in preventing disease,” Winokur said.

State officials are hopeful the Johnson and Johnson vaccine will increase the number of doses administered in the state. The single dose COVID-19 vaccine may be appealing to those who want the convenience of a one-time shot, Ekstrand said.

“We are committed to understanding and eliminating barriers Iowans are experiencing in getting their second dose of vaccine,” Ekstrand said in an email.

To break down any potential barriers to obtaining the vaccine, Winokur said Iowans should be allowed to get the second dose wherever they want. If they got their first dose at a local clinic, for example, they should have the ability to go to a different vaccine provider, such as a pharmacy.

It would also help if individuals can get the second shot on their own time, rather than be scheduled with a specific appointment, Winokur said.

“As vaccine has become more plentiful, this is much more standard and should help people fit the second dose into their day-to-day schedule,” she said.

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