Though the Delta variant of COVID-19 is often pegged as the catalyst for the most recent wave of the virus, a less common variant known as Mu was discovered in western Kentucky during genome sequencing of tests not long after, a public health official with the Purchase District Health Department (PDHD) said.
The Mu variant isn’t very widespread yet — with an incidence of approximately 0.1% — but health officials are concerned with the dissemination of additional variants that could be more resistant to immunity from vaccines and previous infections. The emergence of the Mu variant comes as the Delta variant is already circulating in western Kentucky and across the country.
The Delta variant of COVID-19 has overrun western Kentucky hospitals and public health departments with cases and hospitalizations in recent weeks. Paducah hospitals had to bring in national guard members to aid strained staff earlier this month, and some small public health departments in the region have had challenges with contact-tracing positive cases.
The CDC states the Delta variant of COVID-19 is more than twice as transmissible as other variants — even in some vaccinated individuals — with an incidence of approximately 99% in the U.S. COVID-19 cases in children and adolescents have become more common but not more severe since the Delta variant became widespread.
Moderna President Stephen Hoge — leading the company responsible for creating one of the COVID-19 vaccines — recently told CNBC the Delta variant is so contagious that it may be responsible for the recent COVID-19 case surge in conjunction with waning efficacy of vaccines administered earlier in the pandemic. But he also said the variant is not “an immune escape variant,” meaning the variant hasn’t been able to significantly dodge the immune system.
Variants continue to circulate as the Food and Drug Administration (FDA) is reviewing the necessity of COVID-19 booster shots for the general public. Western Kentucky health officials said there is the possibility for new, potentially dangerous variants to emerge as vaccination rates lag across the region.
Dawn Of Delta
The World Health Organization (WHO) tracks multiple COVID-19 variants on its website. The Delta variant, which is currently classified as a “variant of concern,” is the most prominent variant in the region, said Blake Johnson, senior epidemiologist with the Christian County Health Department (CCHD).
“Unlike previous lineages that didn’t have as much of an impact on pediatric cases, we are seeing more and more children becoming sick and requiring hospitalization,” Johnson said of the Delta variant. “During the summer, it looked like we were finally able to see the proverbial light at the end of the tunnel. But with the introduction of Delta and the low vaccination rates, especially in the South, our medical infrastructure is drowning.”
The WHO states a variant of concern is one that demonstrates an increase in transmissibility or detrimental change in COVID-19 epidemiology; increase in virulence or change in clinical disease presentation; or decrease in effectiveness of public health and social measures or available diagnostics, vaccines and therapeutics.
As of Sept. 22, 32.15% of eligible people in Christian County are vaccinated, according to data from the Kentucky COVID-19 dashboard. Johnson said low vaccination rates are cause for concern among many health workers.
“This new surge has nurses, doctors, respiratory therapists and other healthcare workers remembering what it was like to go down the hall of the ICU and put dialysis catheters into each patient,” Johnson said. “The memories of holding a patient’s hand or being the bridge of communication for families that could not see their loved ones is becoming a reality again.”
A New Variant
The Mu variant, which the WHO currently classifies the Mu variant as a “variant of interest,” was identified during genome sequencing of tests. Though Johnson said the CCHD hasn’t been notified of any Mu variant cases, Dee Owen with the COVID-19 testing team at the PDHD said the Mu variant has been in McCracken County for a “couple months.”
“[A genome sequencing lab in Frankfort does] random sequencing when they start to see a lot of cases, say, in one county,” Owen said. “They will randomly sequence different samples from that county, and if it shows up as, say, a Delta variant, and it shows up in three or four of those samples, then they know that sequence is in that area.”
The WHO states a variant of interest is one that is predicted or known to demonstrate increased transmissibility, disease severity, immune escape, diagnostic or therapeutic escape and is identified to cause significant community transmission or multiple COVID-19 clusters. Further data is required for it to become a variant of concern.
Owen said getting vaccinated against COVID-19 prevents the development of additional variants because the available vaccines have proven effective against all variants thus far.
“As long as there are unvaccinated people, that’s going to be a vector for the virus to mutate,” Owen said. “It’s just going to continue mutating. That’s the nature of a virus. If it can’t get in one way, it’ll mutate and find a way.”
The same data from the state’s dashboard shows that 54.77% of eligible people in McCracken County are vaccinated, slightly below the state total of 60%.
Booster Shots Ahead
COVID-19 variants primarily develop in unvaccinated individuals. To combat the waning efficacy of the current vaccines against COVID-19 variants, the CDC recommends individuals should get a COVID-19 booster shot 8 months after receiving their second dose of the Pfizer or Moderna mRNA vaccines, pending FDA approval.
The FDA approved for emergency use on Aug. 12 a third dose of mRNA vaccines for certain immunocompromised individuals — specifically solid organ transplant recipients or those with an equivalent level of immunocompromisation — to provide further defense against the virus.
“After a thorough review of the available data, the FDA determined that this small, vulnerable group may benefit from a third dose of the Pfizer-BioNTech or Moderna Vaccines,” said FDA Acting Commissioner Janet Woodcock in a statement.
Vaccine advisors for the FDA met earlier this month to discuss the need for boosters among the general public, where they approved boosters for people aged 65 and older and those at high risk but not everyone 16 and older. Some advisors said there is not yet enough data on the safety and efficacy of boosters to warrant administering third doses to younger people.
Although Pfizer officials and President Joe Biden have urged the widespread use of boosters in the fall, the CDC is urging state and local health officials to hold off administering boosters to the general public until the FDA approves them and the CDC provides guidance on their use.
Some western Kentucky health departments have already prepared to administer third doses to the immunocompromised.
