New versions of omicron are fueling an increase in COVID-19 cases in North Texas
A report from UT Southwestern Medical Center says two omicron sub-variants, BA.4 and BA.5, account for more than 75% of the COVID samples tested by its researchers. Dr. James Cutrell, Program Director of the center's Infectious Diseases Fellowship Program, said the resurgence wasn’t a complete surprise, but there were some unexpected aspects of BA.4 and BA.5.
Surprising aspects of BA.4 and BA.5
What really has gotten our attention about BA.4 and particularly BA.5 is that the virus is evolving to become more evasive or able to better escape our immune protection from the vaccines and from prior infection, as well as increasingly easily spread or transmissible to other people.
They spread faster?
Probably about 20% to 30% faster than the original Omicron variant or some of the earlier subvariants we saw back in the early spring.
Some interesting data suggests the way BA.5, in particular, is more efficient at entering into cells and leads to higher spikes of the viral load we're seeing in the upper airways, which probably explains at least part of the reason why it's more easily spread.
Are the vaccines and the one or two boosters we've had effective against four and five?
They're not as effective against four and five at preventing any infection. And so we are seeing an increase in what we would call reinfection, meaning people who've had COVID before, including people who had Omicron only a few short months ago. We're seeing those individuals getting reinfected with BA.4 and BA.5. We're also seeing individuals who are fully up to date getting infected as well.
Now, prior infection and being fully vaccinated are still largely providing protection against severe disease. And so we haven't seen a significant increase in deaths from BA.4 and BA.5, but we are starting to see a slight uptick in hospitalizations just due to really to the large number of individuals who are getting infected or reinfected.
Will new boosters expected this fall offer more protection against four and five?
The FDA has come out and said all boosters the companies are planning for this fall should be what we call a bivalent vaccine, meaning they have a part of the vaccine-specific to target BA.4 and BA.5. And there is preliminary data that those do provide added protection. You know, I think that it will certainly help.
The question I think that's lingering in many people's minds is if we have to wait till October or November for these new boosters, will they still provide a substantial benefit then, or will the virus have further changed or mutated itself before we get there?
Is this worse than what I would have gotten from some previous variant?
We have not seen evidence that BA.4 and BA.5 are causing more severe disease. Now, we don't know if that's just the virus itself intrinsically doesn't cause more severe disease or if it's infecting individuals who already have that partial wall of immunity from prior infection and vaccines.
Fortunately, we aren't seeing trends of significantly more serious disease. But that's something we're going to have to monitor closely because we're these are still relatively new subvariants that we're learning a lot more about their clinical behavior when they infect people.
How do existing treatments for COVID stand up against BA.4 and BA.5?
We still have oral antivirals, and the main one people have been using is Paxlovid, a product that still works well if started early in high-risk individuals who get infected with BA.4 and BA.5.
There's one treatment, the monoclonal antibody bebtelovimab, that does still work against the subvariants. And so that is available and out there.
And there is also the preventative monoclonalfor those that are very high-risk, such as immunocompromised individuals. And that does still appear to provide some protection.
What's important is anybody who's over the age of 50 or has other high-risk features have a treatment action plan in place where they can access testing quickly and then contact their physician to see what treatment options would be best for them, given their other medical conditions, and other medications that they may be taking.
Interview highlights were lightly edited for clarity.
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