Just two months ago, health officials were characterizing breakthrough COVID-19 cases among the vaccinated as exceedingly rare, pointing to hospitalization and fatality data. But now with the number of breakthrough cases on the rise in Lancaster County and elsewhere, infectious disease experts worry vaccine immunity may be waning.
Nearly 30% of COVID-19 admissions at Penn Medicine Lancaster General Health Friday are vaccinated patients, according to health system data. Just 10 days ago, the percentage was about 15%.
Most — but not all — of the infectious disease experts with whom LNP | LancasterOnline spoke blamed, in part, increased viral transmissibility and waning vaccine protection.
“The rise is multifactorial and has to do with the presence of the delta variant, more community transmission, more people (especially the vaccinated) getting comfortable with a baseline risk, and possible waning of protection against infection,” Dr. Amesh Adalja, an infectious diseases physician and senior scholar at the Johns Hopkins Center for Health Security, said in an email.
Adalja added, “However, it’s important to remember the breakthroughs were always expected because vaccines are not force fields or bug zappers. They are designed to prevent serious illness and that breakthrough infections are mostly mild is a win for the vaccine.”
But UPMC officials downplayed the escalating numbers.
“Those numbers, the percentage of people who are admitted who are vaccinated, may be deceptive and may not give a good representation of how well the vaccine is working,” Dr. Graham Snyder, UPMC’s medical director of infection prevention and hospital epidemiology, said during a press conference Friday.
Snyder and other UPMC officials believe breakthrough cases are better assessed with a comparison to the total number of vaccinated individuals.
He also noted some breakthrough cases are likely from patients tested in the hospital for other medical procedures.
A COVID-19 breakthrough infection — or post-vaccination case — is defined as a fully vaccinated individual who tests positive for the virus two weeks after completing a single- or two-dose regime.
Tracking breakthrough cases is important for monitoring the nation’s immunization campaign.
Pennsylvania hospitals have been required to report breakthrough admissions to the state daily since Aug. 12. Not all, though, publicly report this data.
‘The bottom line’
Breakthrough cases have always been expected.
The Centers for Disease Control and Prevention (CDC) has been studying breakthrough cases for months.
Post-vaccination cases — health officials argue — do not indicate a failure of science because no vaccine is 100% effective.
Conventional wisdom has long relied on hospital and fatality data, when touting the success of the COVID-19 vaccines.
“You're likely to become much less ill and much, much less likely to die if you're vaccinated,” said Dr. Joseph Kontra, chief of infectious diseases at LG Health. “And that's the bottom line.”
Kontra added, “Yes, we have a percentage of patients in the hospital who are vaccinated, but they're in the minority.”
It was just a few short weeks ago that breakthrough cases accounted for a small portion of all COVID-19 infections.
A new, statewide report released last week, showed post-vaccination cases represented just 6% of COVID-19 infections from Jan. 1 through Sept. 7. The unvaccinated accounted for 97% of the fatalities.
State health officials declined to say whether breakthrough cases are rising in Pennsylvania. Mark O’Neill, a Pennsylvania Department of Health spokesperson, rather said in an email to LNP | LancasterOnline that updated figures would be available in the next monthly report.
Kontra doesn’t believe LG Health is an outlier.
For example, roughly 18% of COVID-19 patients in Penn State Health’s three hospitals on Friday were fully vaccinated, according to the health system.
‘Not an impenetrable shield’
Emerging data in a handful of states suggest breakthrough infections are climbing.
Rising breakthrough infections have been found in one of five newly diagnosed cases in seven states, including California, Massachusetts and Virginia.
With cases rising and vaccinations falling nationally, CDC Director Dr. Rochelle Walensky on Friday recommended a Pfizer BioNTech booster shot for those aged 18 to 64 at an increased risk of contracting COVID-19 because of workplace or institutional settings.
Boosters are already recommended for older adults, long-term care facility residents and individuals with underlying health conditions.
The rising breakthrough cases — UPMC officials argued during a virtual Q and A with the media — should be examined against the entirety of vaccinations, not just against the total number of hospitalizations and deaths.
This, however, runs contrary to how the effectiveness of the vaccines has been previously measured.
UPMC officials also declined to provide the percentage of breakthrough cases across the health system.
But UPMC officials did encourage Pennsylvanians — whether vaccinated or not — to be aware that they may, when contracting the disease, be contagious to others.
“It’s not an impenetrable shield,” Dr. Donald Yealy, UPMC’s chief medical officer, said of the COVID19 vaccines. “It’s just a really good insurance policy against the bad things that can happen with COVID-19.”
The New York Times contributed to this report.