Testing is one of the key elements of the long-term response to the novel coronavirus disease (COVID-19) and a crucial piece of being able to resume more business and activities.

This continues to be the topic of many questions. Testing options have changed over time and still are changing.

There’s no doubt that more testing would be better for understanding and controlling the spread of the virus. Supplies, staffing and other capacity issues for administering the tests, processing them, and notifying people of their results are ongoing challenges.

Efforts to address barriers to testing continue, and things have improved. The turnaround time is shorter than it was even a few weeks ago for most patients, and targeted testing has been launched at long-term care facilities, where it can have an impact on helping prevent infections and deaths among elderly and other high-risk individuals residing in those settings.

Testing is not being done at every long-term care facility in the county, but is focused on locations where there appears to be a cluster or outbreak. All staff and residents are tested to identify who is infected and then separate them from those who are not. This approach of identifying outbreaks and intervening to stop them from escalating is in line with what the long-term public health response for this disease is expected to look like.How much testing is needed in Snohomish County to get closer to pre-COVID levels of business and activity?

There’s no magic number for how many tests need to be done each week in Snohomish County to confidently reduce social distancing. Models for estimating that number have varied. At this time, roughly 2,500 tests are performed in the county each week, most of them through healthcare providers. Under some models, that is adequate. Others suggest thousands more tests are needed each week.

The CDC has stated its goal is enough testing that the rate of tests that come back positive is 2 to 3 percent. Our current rates are in the range of 5 to 8 percent. Based on this, between 5,000 and 10,000 total test would be needed per week. But once again, exact numbers and positivity rates are likely to vary throughout this response, and the demand for testing by patients also is likely to wax and wane as transmission goes up and down.

Rather than focusing on a specific number of tests, the overarching goal is that anyone who has symptoms of COVID-19 can be tested promptly.

“The right number of tests is the number when anyone who needs one can get one within a day, and then get results in one to two days,” said Dr. Chris Spitters, health officer for the Snohomish Health District.

Ideally, someone could be tested within a day or two of symptoms starting and receive their results the same day or next. This would allow public health staff to be in touch with them quickly to ensure they are isolating until they are no longer infectious and that close contacts are identified and notified to quarantine and monitor for symptoms.

Most local testing is being done through medical providers. The health district has coordinated community testing at drive-thru sites, too. For more than three weeks, the Health District offered testing through such a site in Everett. Testing was also made available in Lynnwood during the last week of April, and Monroe for two days this week. Work is underway to set up at a location in north Snohomish County later this month. Updates will be provided as locations and appointment times are available. Check www.snohd.org/drive-thru-testing for updates.

The testing offered at the drive-thru locations is for people who are experiencing symptoms of COVID-19. Those include any of the following:

• Fever greater than 100.4 degrees
• Cough
• Difficulty breathing
• Chills
• Repeated shaking with chills
• Muscle pain
• Headache
• Sore throat
• New loss of taste or smell

Not everyone with the virus has symptoms and asymptomatic people can spread it to others. However, the reliability of test results and the likelihood of actually spreading the virus appear to be greater when someone is experiencing symptoms.

Aside from facilities with outbreaks or clusters, asymptomatic testing by the Health District would only occur rarely. Currently, the guidelines of the federal Centers for Disease Control and Prevention (CDC), the Washington State Department of Health, and the Health District discourage routine testing among people without symptoms.

What about antibody testing?

New testing technologies can be promising, but more vetting and increased knowledge of the disease itself are needed before we know what role they may play in health care and economic recovery.

Advancements in COVID-19 serology – which is testing blood for antibodies to a virus – is a good example of the need for cautious optimism.

Rather than testing via a nasal swab and looking for the genetic material of the virus to see if it is currently present in the body, blood tests look for antibodies developed by the immune system to combat an infection. Typically, the body continues to produce these protective antibodies for months to years (sometimes even a lifetime).

The goal of serologic testing is to determine whether someone has previously been infected with the virus. And that sounds like just what we need – if we could know who is already immune to COVID-19, we could use that information to help control the spread of this disease in workplaces or other venues. It would also provide a more comprehensive look at how much the virus has spread in our community and thereby inform our methods and margin of safety for resuming activity in the community.

There are important caveats with antibody testing, though. First, most of these tests are new and have had minimal review by the Food and Drug Administration so far. While they can be implemented by emergency use authorization or other emergency measures, more vetting is needed to know how accurate the tests are.

We also don’t know how long immunity to this virus lasts. There are some viruses, like measles, where immunity is lifelong. With others, like influenza, the antibodies will likely last until the next flu season, when you are again vulnerable to the strain or strains of influenza that are circulating.

“We just have no experience on which to base that for COVID-19,” Dr. Spitters said. “So at this time, there’s no systematic recommendation coming from the Health District for use of serologic testing. While we have no immediate plans to implement serologic testing through the Health District, it may be a helpful tool for tracking the pandemic going forward. Its utility for individuals at this time, though, is not clear.”

The CDC has implemented some antibody testing in special circumstances, and other providers or agencies may choose to do so, as well. The testing is expected to be helpful in estimating the background level of infection in the community. Based on current estimates, public health experts believe 5 percent of people, maybe fewer, have been infected. That leaves 95 percent with no exposure or immunity. Antibody testing could better inform that estimate.

It’s important to note that antibody testing is to see if people were previously infected. It is not the appropriate diagnostic test for people who are currently experiencing symptoms. Those who are interested in antibody testing can contact their medical provider to ask about options and should also check with their insurance plan to see if it is covered. A positive antibody test is not a guarantee that they won’t be infected again or that they won’t infect others.

Is it safe to be tested?

Some people’s reactions to this pandemic have generated a number of misunderstandings, rumors and outright falsehoods. Some of these have caused people to worry about the safety of testing.

One such rumor is that testing is somehow spreading the virus, either unintentionally or intentionally by contaminating swabs. This is not true. Trained staff administer the tests using personal protective equipment. The testing kits are manufactured, distributed and handled safely.

Another concern that has been expressed by some is that they will be required to go to an isolation-and-quarantine facility if they test positive. People who test positive do need to isolate, but the majority can do so at home. Isolation requires staying away from others, and if you can do that by remaining home and keeping distance from household members, that is the preferred option.

The isolation-and-quarantine facility provides a place for people who cannot isolate safely at home. This may be because they do not have stable housing or because they cannot reliably keep distance from others in their household. However, the vast majority of people who test positive in Snohomish County isolate at home. Likewise, the vast majority of contacts can safely pass their 14-day quarantine period at home and do not need to go to a special facility for doing so.

Some people also worry about what a positive test result means for their family or their jobs. If you are ill, you should not go to work or other activities, and employers should send ill employees home. That is true whether you test positive for COVID-19 or not.

Close contacts such as family members who live in the same household will be asked to stay home and away from others for 14 days while monitoring for symptoms. You will not be forced to leave your children or other family members if you test positive, though you should avoid close contact with them while you are ill. This can be accomplished by designating a room or area for the person who has COVID-19 to spend most of their time, with limited contact in common areas as well as frequent cleaning and disinfecting in any shared spaces like bathrooms or kitchens.

We plan to continue providing updates on testing. We urge anyone with specific questions about symptoms and whether they should be tested to contact their medical provider or local community clinic for guidance.