With Covid, how many antibodies are enough?

by Brian on March 13, 2022

in Cancer,Covid-19,Health,Science

Is my body capable of producing antibodies against Covid-19 following my four Pfizer doses? Or, because I am immunocompromised due to past cancer treatments, does my immune system leave me bereft of antibodies even after multiple jabs? And most important: Would I want to know, or would I prefer to “act as if” and hope for the best?

Antibody treatment for the immunocompromised

This question has been reverberating in my brain for as long as Covid vaccines have been available. From 2018 to 2019, I received a bi-monthly injection of Gazyva, an immunotherapy drug, to shrink the tumors of my lymphoma. Gazyva and its close cousin Rituximab are highly effective but, at the same time, are among the most harmful drugs when it comes to depleting the body’s ability to produce antibodies.

Most people with this antibody problem have taken Gazyva or Rituximab more recently than me, but still I was curious – and fearful.

There is a simple blood test to check whether your body can mount an antibody response. But the HMOs in Israel don’t offer it because, as my hematologist told me, “We just don’t know what the numbers mean.”

That is, if your IgG levels for the “Anti-S” Covid test contain more than 50 au/ml of antibodies, you’re considered to have had a response. But does that protect you? What if you have 1,000 au/ml? 10,000 au/ml? No one knows yet what number is going to do the job. So, the HMOs don’t want to pay for it since they don’t know what to do with the answer.

You can, of course, purchase a serological test privately. At NIS 217 ($65), it’s not a huge impediment. 

I had pretty much decided to stay in the dark…that was, until Evusheld became available in Israel in February.

Evusheld is a new medication from AstraZeneca designed specifically for people who are immunocompromised. Unlike Paxlovid or monoclonal antibodies such as Regeneron’s REGN-COV2, which are given after one has contracted Covid, Evusheld is administered before you get Covid and gives you all the antibodies your body didn’t create on its own in response to the vaccines.

According to the U.S. CDC, about 7 million people in the U.S. are considered immunocompromised, whether from cancer, an organ transplant, or an auto-immune disease such as rheumatoid arthritis.

Evusheld is what’s known as “a passive vaccine.” It combines two monoclonal antibodies (tixagevimab and cilgavimab) given in two shots that bind to different sites in the virus, preventing it from entering the cells and reproducing. Evusheld results in an 83% reduction in the rate of symptomatic coronavirus, with protection lasting for six months. The drug is also appropriate for people who had an extreme reaction to one of the main Covid vaccines and, as a result, can’t take more.

My doctor felt I should get Evusheld as I tend to progress from cold or flu to pneumonia more rapidly than people who haven’t had cancer treatments. But if it turns out I do have Covid antibodies, then I wouldn’t need Evusheld, right? 

Had the time finally come to test my levels?

I decided to go for it. 

So, on a recent Tuesday, I visited the “Executive Checkup” center on the first floor near the main entrance of Hadassah Medical Center’s Ein Kerem campus.

Executive Checkup is unlike anything I’ve seen in Israeli medicine. A tastefully decorated space with soft lighting, architectural flourishes, comfy chairs, free WiFi and the kindest, English-speaking front-desk staff, it was worth the price just to enter. The nurse who took my blood was so gentle I didn’t even feel the needle prick.

All that was left to do was wait for the results. They came 24 hours later.

I had 6,684 au/ml of antibodies. Hallelujah! I have protection as a result of the vaccines, I rejoiced. Or perhaps I had an asymptomatic case at some point in the last two years and never knew it.

Not so fast, cautioned my doctor, throwing her usual pragmatic water on the flames of my enthusiasm. “There’s not enough data. You should still get the Evusheld.”

An unauthorized visit to Dr. Google was no more conclusive. No website or journal was willing to state whether my 6,000+ antibodies bodes well. The armchair experts I reached out to on social media were similarly stumped.

I have a prescription for Evusheld now. Will I follow through and get it? The side effects from getting a couple of Evusheld shots are supposedly no more than from the vaccines, and all I experienced from my Pfizer jabs was a sore arm and a bit of nausea in the first couple of days.

If I need any extra inspiration, maybe I should listen to my friend Laurie Kleinman Heller who has been urging me to get the Evusheld shot after she received hers. 

Laurie was interviewed on Ynet about her own terrifying situation (she has an immune deficiency known as CVID as well as lymphoma) where she makes zero antibodies. For the duration of the pandemic, she’s been mostly confined to indoors. “The most remote place I go to is to the park across the road,” she says. 

All that’s changed now.

Raya Cohen, a nurse, was even more emphatic. “There are quite a few people like me who have been imprisoned for almost two years,” she told Ynet. “I need this vaccine like breathable air.”

Evusheld or not, we all could use a little more air to breathe at this point.

I first wrote about my to-Evusheld or not-to-Evusheld dilemma for The Jerusalem Post.

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