A pilot testing project in three Omaha Public Schools buildings found COVID-19 infections that were not identified by outside testing, suggesting that infections and case rates in schools were higher than what was being reported.
The school district partnered with the University of Nebraska Medical Center and others to pilot the testing program. The program combined saliva testing intended to detect any symptom-free infections among students and staff and environmental monitoring based on testing wastewater and analyzing air and surface samples.
Infection rates detected during the five-week program were 2½ times higher for staff and nearly 6 times higher for students than what routinely was seen through absences reported to district schools for positive tests, suspected COVID-19 symptoms or high-risk exposures.
In addition, the researchers found almost 10 times the cases per capita than what was observed through community-based testing in Douglas County.
“This data shows the prevalence of (coronavirus) infection in school-aged children is being dramatically underestimated,” Dr. Jana Broadhurst, the principal investigator for UNMC’s portion of the pilot project, said in a statement.
Broadhurst said researchers now know that the majority of people infected with COVID-19 have no symptoms, and that the proportion is particularly high among children. If health officials aren’t looking for such cases, they always will undercount cases, she said.
The testing, Broadhurst said, allowed researchers to identify and send home staff and students who otherwise wouldn’t have been identified, reducing the risk of spread in the schools. Such testing also could help provide insight into how much a disease is spreading in a community where access to testing is limited.
The five-week project was conducted in November and December, a time when transmission in Nebraska was spiking. All three participating schools — Norris and Marrs Middle Schools and Bryan High School — are in the south part of the Omaha metro area, an area hard hit by the virus and where positivity rates often have exceeded those in the rest of Douglas County.
The research, which has not been reviewed by outside scientists, was published Saturday in an online forum. Other partners in the project were Nebraska Medicine, the University of Nebraska-Lincoln and OneWorld Community Health Centers.
One ongoing question during the pandemic was whether transmission is occurring within schools or whether the cases that occur there are being brought into schools by staff and students.
Broadhurst said the answer is complicated. The researchers sequenced the genomes of some positive samples. They found that the majority of those cases were not part of related transmission chains, suggesting the majority of cases were arriving from the community.
They also addressed that question through the testing of air and surface samples within the schools. The majority of samples were negative, including in cafeterias where masks temporarily are off.
But they did detect the virus in air samples in two choir rooms. One of the choir rooms also yielded a positive surface sample. Broadhurst said the environmental testing demonstrates how the testing approach may identify some activities that require modification in order to keep the environment as safe as possible.
During the pilot period, OPS was using a hybrid teaching model that staggered student attendance to decrease numbers in its buildings. About one-fourth as many students were present each day compared to a typical school year. Staff and students were required to wear masks in school buildings, where air exchange systems also had been improved.
The researchers screened asymptomatic students and staff each week with a saliva test using a streamlined version of the gold-standard PCR method. Nearly 100% of staff participated, and 12% of students signed on.
Ultimately, the researchers analyzed 2,885 saliva samples from 773 symptomless staff and students. They detected 46 positive cases, 22 in students and 24 in staff. Those figures represented a 5.8- and 2.5-fold increase in case-detection rates among students and staff, respectively, compared to outside testing mechanisms.
The cases the researchers identified were reported to the individuals, the schools and the local health department for contact tracing and isolation, just as other positive cases are reported.
The researchers also detected the coronavirus’s genetic material in wastewater samples from all three schools.
According to OPS documents filed in November, the district planned to fund the $2.3 million pilot through a combination of OPS general fund and grant money. OneWorld’s portion, nearly $80,000, also was to be covered by general fund and grant money.
Broadhurst said the researchers expanded the program to three schools in North Omaha in January through March, which will provide additional information.
“There is the intent to utilize what we have learned through the pilot to extend testing across the district,” she said.
Nationally, she said, momentum is building for school-based testing programs, with such initiatives seen as a key component of reopening schools safely.
While how testing is done may look different in every district and every state, Broadhurst said, the pilot provides a “proof of concept” that it can be done successfully in an urban district and that it can make an immediate impact on the safety of schools by quickly identifying cases.
“Our results show as many as nine in 10 student COVID-19 cases and seven in 10 staff cases might be missed by conventional reporting,” she said. “Doing this kind of testing can help lessen transmission in schools because of the ability to better isolate, trace and manage school activities.”
Now that you’re vaccinated, here's what you can and can’t do
CDC guidance contains activity recommendations for fully vaccinated people in private settings and includes:
Visiting with other fully vaccinated people indoors without wearing masks.
Visiting with unvaccinated people from one other household indoors without wearing masks or staying 6 feet apart if everyone in the other household is at low risk for severe disease.
Refrain from quarantine and testing if no symptoms of COVID-19 are experienced after contact with someone who has COVID-19.
The CDC has also updated its guidance to say fully vaccinated people can travel within the U.S. without getting tested for the coronavirus or going into quarantine afterward. Read more about that here:
For the most up-to-date guidance from the CDC, go to the CDC's COVID-19 site.
The CDC says that anyone who is fully vaccinated should continue to take these precautions when in public, when visiting with unvaccinated people from multiple other households, and when around unvaccinated people who are at high risk of getting severely ill from COVID-19:
Wear a well-fitted mask.
Stay at least 6 feet apart from people you do not live with.
Avoid medium and large in-person gatherings.
Get tested if experiencing COVID-19 symptoms.
Follow guidance issued by individual employers.
Follow CDC and health department travel requirements and recommendations.
Here’s a list of 10 things you should know about potential COVID-19 vaccine side effects, according to the Centers for Disease Control and Prevention and Harvard Medical School:
- The Pfizer-BioNTech COVID-19 Vaccine and Moderna COVID-19 Vaccine both require two shots in order to get the most protection. You should get the second shot even if you have side effects after the first shot, unless a vaccination provider or your doctor tells you not to get it.
- Side effects from the second injection may be more intense than the ones you experienced after your first shot.
- The most commonly reported symptoms are pain, redness and swelling at the site of the injection. Other common symptoms reported include tiredness, headache, muscle pain, chills, fever and nausea.
- You may take acetaminophen, aspirin or antihistamines for any pain and discomfort you may experience after getting vaccinated — as long as you have no medical conditions that prevent you from taking them normally.
- It is not recommended that you take pain relievers before being vaccinated in an effort to prevent side effects. They may interfere with the vaccine’s effectiveness.
- If you have pain at the vaccine’s location, keep the arm active and use a clean, cool, wet washcloth over the site.
- For a fever, drink plenty of fluids and dress lightly to remain as cool as possible.
- The symptoms should improve within two or three days.
- Call the doctor if redness and/or tenderness at the injection site worsen after 24 hours.
- Call your doctor if any other symptoms seem to be worsening or not improving after two to three days
Can I get COVID-19 after being vaccinated?
Like other vaccines, such as the flu shot, the COVID-19 vaccines work by teaching the immune system how to recognize and fight the virus that causes COVID-19. It typically takes two weeks after vaccination for the body to build immunity against the virus, according to the Centers for Disease Control and Prevention.
Because of this, it is possible for a person to get COVID-19 before or just after vaccination, and then get sick because the body hasn’t had enough time to develop protection.
Dr. Michael Lindberg, chief medical officer at Monadnock Community Hospital in New Hampshire, said that while possible, it’s “very uncommon” for someone to become infected with COVID-19 after vaccination.
Should I still get tested after getting vaccinated?
If you’ve been vaccinated and are showing symptoms of COVID-19, then yes, you should get tested.
If you have been vaccinated and don’t have symptoms, however, you don’t need to get tested even if you suspect you’ve been exposed to the virus, per guidance from the Centers for Disease Control and Prevention.
When will we hit herd immunity?
Scientists estimate that potentially 75% to 85% of the population needs to be immune to reach herd immunity for COVID-19. Some estimates are higher, at around 90%. As of March 29, 15.8% of the U.S. population had been fully vaccinated, 28.6% had gotten at least one dose.
How long will we have to wear face masks?
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said in February that even with increasing vaccinations, it’s “possible” Americans could still be wearing face masks and coverings in 2022.
Also contributing to this report: The News & Observer (N.C.), The Keene Sentinel (N.H.), Dayton Daily News (Ohio) and The Staten Island Advance (N.Y.)