COVID

We’ve reached the point where almost everybody has had COVID or been vaccinated. What does that mean?

As Massachusetts starts a new chapter of the pandemic, rising community immunity plays a role in keeping COVID-19 cases low.

By Abby Patkin

June 5, 2023

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By now, you’ve likely got some amount of COVID-19 antibodies coursing through your veins, whether from vaccines or a previous infection — maybe both. 

In fact, a new report from the Centers for Disease Control and Prevention suggests that nearly all Americans had some level of COVID antibodies in their system as of early last fall.

The article, released last week, presents data from a CDC study tracking antibodies in about 143,000 blood donors nationwide. By the third quarter of 2022 — the most recent data available — an estimated 96.4% had COVID antibodies. 

About 23% had antibodies from infection, while 26% had them solely from vaccination. Nearly 48% had immunity from both, and studies have shown that this hybrid immunity offers better protection against COVID-19 than a vaccine or infection alone. 

All told, rising community immunity is likely a main factor contributing to the lower case rates Massachusetts has seen in recent months, according to Dr. Shira Doron, chief infection control officer for the Tufts Medicine health system and hospital epidemiologist at Tufts Medical Center.

“We have gotten to a place where people have had the opportunity to be vaccinated multiple times,” Doron told Boston.com. “Almost everyone in this country has been infected once, and many people multiple times. And we have really highly effective treatments for those who qualify for them.”

All that bodes well for starting a new chapter of the pandemic, Doron explained. 

“I would say we’re at a place where COVID-19 is very much like all of the other respiratory viruses that we contend with on a regular basis,” she said. 

The current state of COVID-19

One sign of the changing times is the end of state and federal COVID-19 public health emergencies last month. (The World Health Organization also declared the global health emergency over.) 

While public life has largely returned to pre-pandemic norms, the healthcare system has changed, according to Doron. Even today, she said, healthcare providers are still invested in ensuring that patients are vaccinated against COVID-19, know which symptoms to look for, test early, and seek treatment when needed.

The CDC data also shed some light on the need for continued vaccination efforts, indicating that the prevalence of hybrid immunity is lowest in adults older than 65 — a population at high risk for severe illness or death, and the age group with the highest COVID-19 vaccination rates in the U.S. 

According to last week’s report, “low prevalence of infection-induced and hybrid immunity among older adults reflects the success of public health infection prevention efforts while also highlighting the importance of older adults staying up to date with recommended COVID-19 vaccination, including at least 1 bivalent dose.” 

Likewise, the end of the public health emergencies hasn’t slowed COVID-19 research, according to Dr. David Walt, professor of pathology at Harvard Medical School and Brigham and Women’s Hospital.

Walt led a team of researchers in identifying a potential biomarker that could help inform the diagnosis and treatment of long COVID. The research also bolstered a theory about the existence of reservoirs of lingering virus in long COVID patients’ bodies. 

“I think that the researchers who got involved in COVID are not just going to shut down those parts of their labs or their clinical studies simply because the emergency is declared over,” Walt told Boston.com. “I think everybody who entered this from a research perspective expected that this is going to be a long-term drain on our health care system, and I think they have the fortitude to push through.”

What’s the outlook? 

Ultimately, however, COVID-19 offers no guarantees — especially with case counts. 

“I would not at all say that it’s likely that the numbers will stay where they are today forever,” Doron cautioned. “Nor do I expect them to even last for several more months.”

She believes the future of COVID-19 is shaped like a sine wave, marked by periodic ups and downs as the virus surges and retreats — much like the flu.

“We can sustain increases and decreases [of infections] over time … without it being likely that we will have waves of hospitalizations and deaths that are as large as what we saw in the earlier days of the pandemic,” Doron said.

“That being said,” she continued, “anything is possible with the virus, obviously. It could mutate to be both more immune evasive and more severe; there’s nothing that says that it can’t. And so we’re always ready to ramp back up as needed.”