The first weekend of December, nationwide delta-driven coronavirus cases were relatively low, and there had only been nine reported cases of the omicron variant in the United States. Since none of those cases had yet been reported in North Carolina, 11 college friends and I decided to keep our plans to gather there for a post-grad reunion.

Vaccinated (and in some cases, boosted), and masked up, everyone traveled to stay with our friend in Charlotte.

Radio Advisory episode: Omicron—what it means for health care policy

A few days after I returned home, I received a seemingly endless series of texts. "Guys, I am so sorry, I just tested positive for Covid," the first victim said.

At the time I felt fine, but one by one, similar messages were sent by nearly everyone in the group chat—including me.

How I became a miniature case study in variant uncertainty

All 12 of us were fully vaccinated, and some were also boosted. So, when 10 of us tested positive for coronavirus, we were genuinely shocked. Notably, the only two who did not test positive (but were equally as exposed) were vaccinated and also had natural immunity from previous infections.

Thankfully, as vaccinated, otherwise healthy 25- and 26-year-old women, we experienced somewhat mild symptoms, largely consisting of headaches and congestion. I also slept for about three days straight. But, as a Daily Briefing editor who has spent the entire pandemic reading and writing about Covid-19, I couldn't stop thinking about the virus's unexpected ability to evade everyone's vaccination-induced immunity.

At the time, omicron had just been labeled a "variant of concern" by the World Health Organization, and preliminary reports indicated that, given the variant's number of genetic mutations, it would be much more likely to evade vaccine protection than previous variants.

So even though omicron accounted for only about 3% of all coronavirus cases in the United States at the time, I strongly suspect we were among the variant's earliest U.S. victims.

However, like most other Covid-19 patients, I'll never know for sure.

Why so few people learn which variant they're infected with

The first reason why so few people know which variant they have? Most coronavirus samples are never genetically sequenced.

The United States has significantly improved its surveillance efforts since the beginning of the pandemic, going from sequencing fewer than 1% of all positive coronavirus samples to now sequencing between 5% and 10% of all positive samples.

CDC Director Rochelle Walensky last month said around 80,000 samples were being sequenced per week, which represents around one out of every seven positive samples.

300+ Covid-19 treatments are in development. Which ones will really matter?

But even if you're one of the rare individuals to have your coronavirus sample sequenced, you'll likely never learn the results. Variant shares are generally reported to public health entities—not to infected individuals—leaving doctors and patients relatively uninformed when making personal treatment decisions.

Genomic sequencing in laboratories can also take about a week, too long for the early antibody treatments that have been found to reduce hospitalizations for specific variants to work.

In addition, many Americans have been relying on rapid at-home Covid-19 tests, which are generally neither sequenced nor reported to public health entities.

Does variant distinction actually matter? Sometimes.

According to the New York Times, there is not approved test to determine which variant is infecting an individual. And while U.S. officials have endorsed a workaround approach that can identify omicron's genetic signature, experts say it's not feasible for overwhelmed health systems to employ in each instance.

In mild cases (such as mine), it may not matter much to know which variant is causing an infection. But that information can be clinically significant for hospitalized individuals with severe Covid-19 cases.

For instance, monoclonal antibody treatments greatly benefit high-risk Covid-19 patients with the delta variant. But of the three currently authorized treatments, two are "powerless" against omicron, according to an article in Nature—meaning only one infusion formula manufactured by GlaxoSmithKline (GSK) and Vir Biotechnology has the ability to prevent severe illness due to omicron.

Unfortunately, this antibody treatment is in very short supply. So, health systems are using regional estimates based on reported sequencing to decide which antibody treatment would most likely serve their communities, the Times reports.

In particular, many have concluded that a community of largely delta patients would benefit most from the antibody drugs manufactured by Regeneron and Eli Lilly, while communities where omicron cases are predominant would benefit from the GSK and Vir Biotechnology treatment.

According to the Times, federal officials stopped shipments of the Eli Lilly and Regeneron antibody treatments when CDC reported (and later retracted) claims that 73% of U.S. Covid-19 cases were due to the omicron variant. But that decision was met with backlash from state leaders who argued patients in their state were still infected with delta and would have benefitted from the treatments.

So, while America continues to deal with an uneven mix of both delta and omicron variants, tailoring treatments to each patient will be "extraordinarily difficult," said Alex Greninger, assistant director of the clinical virology laboratories at the University of Washington Medical Center.

Mark Seidner, an infectious disease clinician and researcher at Massachusetts General Hospital, said his health system stopped using the Regeneron and Eli Lilly antibodies that are not effective against omicron and are "anxiously awaiting" more doses of the effective treatment by GSK and Vir Biotechnology.

"We're in a holding pattern and it's a terrible time to be in that place," he said.

So, while not knowing which variant I had been infected with didn't matter too much to me—aside from sparking my curiosity—for others, the distinction "could mean the difference between life and death." (Jewett, New York Times, 1/3; Howard, CNN, 12/3/21; Kozlov, Nature, 12/21/21)