As the United States begins to loosen COVID-19 restrictions, the Centers for Disease Control and Prevention (CDC) has sounded the alarm of the Delta variant (B.1.617.2) of SARS-CoV-2, which originated in India and now accounts for most cases in the United Kingdom. The Delta variant is approximately 60% more transmissible than the highly infectious Alpha variant (B.1.1.7) identified in the United Kingdom in late 2020. In addition, the Delta variant is moderately resistant to vaccines, which reinforces the reality that COVID-19 testing is crucial in the fight against the spread of the virus .
Six months after COVID-19 vaccines first started rolling out, 3 billion doses have been administered around the globe . While vaccinations are rising, testing has been on the decline. Stephen Morse, Ph.D., professor of Epidemiology at the Columbia University Mailman School of Public Health says that vaccines are very good at preventing severe illness and, although they look very promising for preventing transmission, we don’t yet know how effective they are at this. Respiratory infections are hard to control and with the emergence of more transmissible variants continued precautions will be needed.
“Natural selection will favor the variants that can spread the fastest and those are eventually going to become dominant. It’s very important to catch those as early as possible so they can be stopped,” Dr. Morse explained. “We remain concerned about the emergence of new variants that could evade the protection conferred by vaccines. Finding them and tweaking the vaccines also requires testing.”
Dr. Morse continued, “Testing really is important because if a variant is more transmissible, it would spread faster and we need to be more vigilant to catch it much sooner.” As the virus mutates, there is also a possibility that new strains will produce more severe symptoms, making it all the more important that tests are kept up to date to detect new variants as they emerge. “It’s still a cat and mouse game, but the testing has been very successful. It just shows that we really need to keep on our toes and do more and more testing, not less,” said Dr. Morse.
As far as what kind of testing is needed, Dr. Morse says PCR-based molecular tests remain the gold standard. “There are other tests that have their uses, but they have to be interpreted with caution,” said Dr. Morse. “There has been a lot of discussion about how sensitive the test has to be to be useful, because we don’t know how much virus you need to become infected. But obviously we would like to have the most accurate results we can in the circumstances.”
What can we learn from the last twelve months?
Lockdowns and public health measures have slowed down transmission all over the world but at a great cost to personal lives and to the economy. In theory, better disease mapping and the use of prescribed precautions in local areas should prevent the spread of future viruses, cutting the chain of transmission so extensive lockdowns can be avoided. Dr. Morse believes this hasn’t yet been successful but by acting quickly in the future – with a well-coordinated and well-communicated plan at every level to stop an emerging virus in its tracks – a global disaster of this scale could be avoided.
“I’ve spent about 30 years working on how to stop emerging viruses,” said Dr. Morse. “We can learn from our mistakes.” The biggest mistake we made during this pandemic is initially restricting the population perceived as at risk, according to Dr. Morse. “The people we were letting through the airports and letting walk around were responsible for most of the transmission. Most of the infected people seemed healthy but were spreading virus. Testing – good testing – on a wider scale would really have picked that up much, much sooner.”
Listen to Dr. Morse’s conversation with Manoj Gandhi, M.D., Ph.D, senior director of medical affairs at Thermo Fisher Scientific, on Thermo Fisher’s “Science with a Twist” podcast.
To learn more about Thermo Fisher Scientific’s COVID-19 Testing Solutions, please visit thermofisher.com/covid19.