How recovered COVID patients impact herd immunity timeline

Vaccination and infection are the two ways to get to herd immunity
Posted at 8:31 AM, May 20, 2021
and last updated 2021-05-20 08:31:19-04

(WXYZ) — Colleen Zammit and her family know COVID all too well.

In the fall Zammit, her husband, and her teenage son got the virus. Then her two daughters got COVID this past spring. Fortunately, for all of them, it was mild and they all recovered.

"Thankfully we all handled it very well," said Zammit, who is on the other side now and faced with an increasingly pressing question: Does she get vaccinated? Does she have her two eldest kids get vaccinated?

She’s just not sure.

"We’re just not inclined to get vaccinated for something that we’ve already had," said Zammit who tested positive for the antibodies on April 29, when she donated platelets.

"If the boosters are something that are going to happen, I think we’ll all be going in to get a booster shot," she continued, explaining that she was simply holding off until her immunity runs out.

Zammit and her family fall into a large — but hardly discussed — segment of the population: those who have recovered from the virus and now have antibodies. According to medical experts, there are two ways to reach herd immunity: vaccination and infection. Yet, this latter group is rarely discussed in the "Vaxx to Normal" plans.

"I’m very frustrated with the continued lack of discussion about all the people who have been infected and recovered," said Zammit.

Starting next week the state will allow in-person work for all sectors of business. That step towards normalcy is possible because last week Michigan hit a milestone: 55% of the population over age 16 had received a shot. While the "MI Vaxx to Normal” plan is based on herd immunity goals, the numbers only include vaccines.

"It’s never talked about in the Vaxx to Normal" in terms of meeting those thresholds," said Zammit.

That’s possible, according to Dr. Joel Fishbain, an infectious disease doctor with Beaumont Health, because it would be harder to take into account the staggered — and vacillating immunity — for people who have recovered.

Still, Fishbain does agree we may be focusing on the wrong data when trying to gauge how the state is doing on its road to recovery.

"Maybe, instead of focusing on some arbitrary number with flawed statistics, because you can’t capture the number you want to, maybe the better answer is get everyone vaccinated and watch the rate of positive tests," said Fishbain, pointing out that current positive test data shows declining spread of the virus.

Of the 36,000+ COVID tests reported last Friday, for example, 6.3% came back as positive, which is the lowest rate since mid-March.

Still, when it comes to the question of recovered patients getting vaccinated, doctors, like Fishbain, are encouraging individuals to still do so

"While I agree it’s unlikely that someone who recovered from documented COVID is going to get re-infected within 90 days or six months — we don’t think so — the reports are rare but it does happen," said Fishbain. The doctor said he was OK with previously infected people holding off on getting vaccinated in the winter — when shots were hard to get— today, however, he sees no downside in just getting vaccinated.

"The vaccine," he said, "is clearly very effective and very safe, so you know it’s one of those things, well why wait?"

Still, he said the focus should be on getting people with no exposure vaccinated. He agrees Zammit could ultimately wait until her immunity runs out if that’s what she prefers.

"If you’ve had COVID," said Fishbain, "and you don’t want the vaccine that’s fine, but please have all of your friends and family members who didn’t have COVID go get their vaccines."