monoclonal antibodies

Son Of Omicron

“A rose is a rose is a rose.” –Gertrude Stein

Omicron is Omicron is Omicron (except when it becomes something different).

Two-plus years into the pandemic, many Americans are ready to declare the COVID crisis over. But, we have been at this juncture before—at the end of the very first surge (remember “flattening the curve?”), and again as Delta faded. Each time, a new virus variant came roaring back. Why should it be different now?

There are reports of two new sons of Omicron circulating in the world. The original Omicron, or BA.1 has spawned BA.2 and BA.3. While little is known about BA.3 at this time, very early indications are that BA.2 represents an even more infectious variant of Omicron, and it is spreading around the world and the US. This variant of a variant seems to be about 30% more infectious than Omicron BA.1. It quickly overtook BA.1 in South Africa and other countries and has caused a second Omicron surge in Denmark. BA.2 has been detected in 74 countries, and has become dominant in at least 10 of them: Bangladesh, Brunei, China, Denmark, Guam, India, Montenegro, Nepal, Pakistan and the Philippines, according to the World Health Organization's weekly epidemiological report.

In the US, BA.2 has been reported in 47 states and accounts for ~4% of all new infections according to the CDC, and it appears to be doubling fast. Samuel Scarpino, director of pathogen surveillance at the Rockefeller Foundation says that if infections double again to 8%, we will be in another exponential growth phase, or the fifth wave of the pandemic. In other words, BA.2 seems to be quickly backfilling the vacuum left as BA.1 peters out.

While BA.2 clearly arose from BA.1, it carries dozens of additional gene changes, making BA.2 as distinct from BA.1 as the Alpha, Beta, Gamma and Delta variants were from each other. This suggests that BA.2 might soon be given its own unique Greek letter designation.

What does BA.2 augur? While vaccination and prior infection still appear to protect fairly well against BA.2, this variant still seems more adept at skirting the immune system then the original Omicron. An early report also shows that vaccine induced antibodies often fail to neutralize BA.2 in tissue culture, and that the virus better replicates than BA.1 in nasal epithelial cell cultures. Nevertheless, those who have been vaccinated and boosted are 74% less likely to become ill from BA.2.

Hopefully, this reduced immunity will still be enough to provide an immunological redoubt against extensive spread of BA.2. The best thing that could happen is that as we become increasingly immunized by vaccine and infection, it might be enough to continue the drop in BA.1 Omicron infections, and check any surge from the new BA.2 variant. This is speculation at this point, and one thing we have learned over the last 2+ years is that the virus does not often respond as expected.

Then there is this: Very preliminary laboratory data hint that BA.2 might cause more severe disease than BA.1, and it appears capable of foiling some of the key weapons we have against COVID-19. In initial lab studies, a Japanese team reported that BA.2 has structural features that might make it as virulent as Delta was. This prediction of increased virulence was supported by hamster infection experiments, but this has yet to be confirmed or refuted in real-life epidemiological studies. Rest assured, those studies are underway, so we will see.

BA.2 also is almost completely resistant to some COVID treatments, such as sotrovimab, a monoclonal antibody therapy that is currently used against Omicron.

Bottom line: During the Spanish flu, as people wearied of the social restrictions designed to prevent the spread of the virus (there were no vaccines or drugs for flu then), many pushed back against the restrictions, which led to premature relaxation of the mandates. Cities like Denver and Philadelphia, which lifted their mandates early paid a hefty price. Other cities like St. Louis, which took a more cautious approach were relatively unscathed. Let’s hope that we are not relaxing and entering a “control phase” too quickly.

What’s ahead of us is not COVID’s end, but might be the start of a phase in which we continue to invest in measures to continue to shrink the virus’s burden. Success in this is not entirely up to us. The virus will have a say too. Our future will depend both on the virus’s continued and unpredictable evolution and on our responses, both immunological and social. The goal is to get ahead of any new variants with wide spread immunity and a growing formulary of antibody and drug treatments, and, yes, this might also require renewed mandates.

A detailed report  looking at past suspected coronavirus pandemics (e.g., the Russian “flu”of 1889, which was probably a coronavirus) published last August in the journal Microbial Biotechnology, suggested plausible scenarios in which elevated levels of COVID-19 deaths could last another five years or longer. This of course depends on what happens to and after BA.2.

It probably is not quite time to relax all mask mandates or let up on the push to vaccinate.

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Don’t Forget The Drugs: An Update

In these pages last March, I reminded readers to be thankful for the vaccines that prevent COVID-19, but to not forget the antiviral drugs that are being developed that might treat the disease. Both vaccines and antivirals are part of the same quiver of weapons we have to fight the pandemic. In that blog post, I mentioned an experimental drug, molnupiravir that was being developed by Merck and Ridgeback Therapeutics. Well, they just posted an encouraging update. It continues to show success at preventing serious disease when given to high-risk people early after infection. Its only side effects were similar to the placebo, meaning it is very safe. In animal studies, the drug also was effective against different CoV-2 variants, including Delta, and against other coronaviruses including SARS and MERS. Molnupiravir is a “prodrug,” which means that it has no activity on its own; rather it is metabolized after ingestion to an active drug that was developed in the early 2000s to treat hepatitis C.

This is a significant step for being able to easily protect high-risk patients at home. The pill that patients take on their own cuts their risk of hospitalization or death by ~50%. The results were so encouraging that the study was halted after consultation with the FDA. Early termination of studies like this is only done when interim data analyses show such good efficacy of a treatment that it would be unethical to continue enrolling subjects, some of whom would receive placebo, thereby being denied an effective therapy.

The drug slows the spread of the virus in infected people by forcing the enzyme that copies the viral genetic material into making so many mistakes the virus cannot reproduce. That, in turn, reduces the patient’s viral load, shortening the infection and damping the type of over-exuberant immune response (cytokine storm) that causes serious problems in many COVID patients. It was not effective when given to already hospitalized, or advanced, patients. It is on track to be approved by the FDA by the end of the year, and would be the first proven and approved oral antiviral drug for treating COVID-19 (neither ivermectin nor hydroxychloroquine have been proven or approved).

The FDA has already cleared another antiviral drug, remdesivir, for treating COVID-19, but it is only used to treat advanced patients who are already hospitalized (interestingly remdesivir was also originally developed to treat hepatitis C and it is also used to treat Ebola). Several lab-produced monoclonal antibody treatments have also been approved by the FDA for treating mild to moderate COVID-19 and they are more successful than molnupiravir at preventing advanced disease. But both remdesivir and the antibody treatments require an intravenous infusion done in a health care setting, making them more complicated and more expensive than just taking a pill at home, which is a decided advantage of molnupiravir. Finally, one of the more effective approved drugs against COVID-19 is the steroid, dexamethasone, but that is only given to very sick patients since its side effects are significant. Therefore, there is much room in the anti-COVID quiver for effective, simple-to-administer drugs such as molnupiravir. Both Pfizer and Roche also have other antiviral drugs that block viral replication in advanced stages of development. Stay tuned.

As of October 5, 2021, the Milken Institute tracker shows that there are 331 “treatments” for COVID-19 in development worldwide. This effort recently got a $3.2 billion boost from the US Antiviral Program for Pandemics, which is a rejuvenated initiative that was started during the MERS outbreak in 2012, but was tabled after MERS fizzled out. Then there is the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) program, also sponsored by NIH. These programs focus on developing non-vaccine therapies designed to treat not prevent the disease and they include studies of medicines currently used to treat other diseases (including ivermectin, which has yet to be proven effective) as well as studies of new drugs.

While the news about molnupiravir is encouraging, health experts are concerned that the news also could increase complacency regarding vaccines in the vax-hesitant. It is important to realize that prevention (vaccination) is almost always preferable to treatment (drugs).

Get the vax.

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