As of December 12, there have been 79,611,982 total tests reported by the CDC. For the first week of July, between 519,951 and 719,063 people were tested per day. Viral tests, which detect active COVID-19 infections, are the primary type of testing, although antibody tests, which indicate past infections based on the presence of COVID-19 antibodies, are also available.
There are several reasons why testing people for active COVID-19 infections is important.
SARS-CoV-2 is especially contagious because this is the first time that this particular coronavirus is being transmitted among humans. Without a vaccine or herd immunity, the only way to prevent transmission of COVID-19 is by separating people who are infected from those who are not.
People who receive a positive diagnosis should self-isolate to prevent further spread of COVID-19. If people know with certainty that they are infected with COVID-19, they are more likely to take proper precautions, including isolation, social distancing, and mask-wearing. This information is also beneficial to those around the infected individual, as they can avoid contact altogether or exercise more caution when near the infected person.
This is especially important since there is evidence that a significant number of people with COVID-19 are asymptomatic, meaning they never display any of the common signs of illness, or have symptoms to such a mild degree that COVID-19 can be mistaken for another illness, like the common cold. Studies have indicated that anywhere from 40% to 75% of people with COVID-19 are asymptomatic.
Contact tracing is another key part of slowing the spread of COVID-19. Once an individual is diagnosed with COVID-19, contact tracers can notify people who had contact with the infected person that they were exposed to the coronavirus, and encourage them to seek testing as well.
While there is no definitive treatment for COVID-19, individuals who have the illness should still seek medical care, especially if their symptoms are moderate to severe. In the months since the pandemic started, doctors have discovered effective means of treating patients with COVID-19, which can improve chances of recovery.
Additionally, the more people there are being treated for confirmed cases of COVID-19, the more data doctors, epidemiologists, and researchers have to better understand the disease, its effects, and its possible treatments.
Understanding who is infected with COVID-19 and where outbreaks are likely is a critical factor in managing the pandemic, from preparing hospitals for potential surges to safely reopening businesses, schools, churches, and other gathering spaces safely.
As noted above, because of how contagious the virus is, people must know with relative certainty whether they are currently infected with the disease before having contact with others at work, social gatherings, or in other public spaces. Otherwise, they run the risk of spreading the disease throughout their communities.
During widespread lockdowns in March and April, public health experts warned that lifting stay-at-home orders and returning to regular work and social habits without widespread testing would likely lead to a surge in infections. These experts emphasized that effective, widespread testing to prevent outbreaks is a key part of getting the U.S. economy up and running again.
These warnings have come true as several states, such as Arizona, Florida, and Texas, have seen significant increases in the number of COVID-19 cases since they began re-opening in May and June, forcing many places to slow or stop their reopening processes.
Although much of the focus of COVID-19 testing has been on diagnostic testing, antibody, or serology tests, also play an important role in the coronavirus testing strategy.
Because of the prevalence of asymptomatic and mild cases, antibody testing is helpful in identifying who was sick, giving epidemiologists and public health experts a better understanding of the spread of the disease.
On an individual level, knowing if a person has already had COVID-19, and whether they have any immunity to the disease can help in determining whether it is safe for that person to return to work, and other social activities.
As researchers race to develop effective treatments and vaccines for COVID-19, it is useful to study those who have recovered from the disease. Individuals who have COVID-19 antibodies can donate plasma, which researchers are using to learn more about the disease, and develop treatments for it.
There are a few significant challenges facing the U.S. as it attempts to increase COVID-19 testing to the recommended levels.
The main issue with COVID-19 testing in the U.S. is scarcity. After initial issues with producing tests at the start of the pandemic, the U.S. increased its testing capacity significantly. However, as cases begin to surge again in many parts of the country, testing has again become challenging due to a lack of supplies and backlogs at the laboratories that process diagnostic tests.
Questions also remain about the accuracy of both viral tests and antibody tests. A preliminary study of the accuracy of diagnostic tests show that they can return false-negative results anywhere from 20% to 67% of the time, which dramatically decreases their efficacy. The speed with which tests were developed, as well as unknowns about the optimal timing for conducting tests have contributed to inaccuracies. Testing accuracy will likely improve as researchers learn more about the disease.
|Centers for Disease Control and Prevention (CDC)||https://www.cdc.gov/coronavirus/2019-ncov/index.html||The CDC is the United States’ leading national public health organization. Its mission is to protect public health and safety through the control and prevention of disease, injury, and disability in the U.S. and abroad.|
|World Health Organization (WHO)||https://www.who.int/||A specialized agency of the United Nations, WHO is responsible for international public health. Headquartered in Geneva, Switzerland, it has field offices worldwide.|
|Association of Public Health Laboratories (APHL)||www.aphl.org||The APHL is a nonprofit organization in the United States that represents laboratories that protect public health and safety.|