Why are vaccinated people catching COVID? It doesn’t mean vaccines aren’t working

As new COVID-19 cases top 1 million per day in the United States, some are asking why vaccines aren’t doing more to stem the spread of the virus.

The U.S. reported 1,082,549 new COVID-19 cases on Monday, Jan. 3, setting a one-day record, Johns Hopkins University reported.

Those who are unvaccinated are at the highest risk for catching COVID-19 and having more severe outcomes, experts say, but even the fully vaccinated are susceptible.

Here’s what to know:

Why are vaccinated people still catching COVID-19?

Clinical trials showed the Pfizer and Moderna vaccines originally lowered risks of developing symptomatic COVID-19 by about 95%. This means vaccinated people were about 20 times less likely to get the disease than those who didn’t receive their shots, McClatchy News reported.

The Johnson & Johnson vaccine had a 72% efficacy rate among Americans. However, early studies show vaccines may be less effective at preventing the omicron coronavirus variant.

And no vaccines provide foolproof protection against disease, particularly one as prone to variants as the coronavirus, experts said.

For example, the flu vaccine is between 40% and 60% effective, depending on the version of the virus that’s circulating in a given year, the CDC says. Yet, the flu vaccine prevented an estimated 7.5 million flu illnesses, 105,000 hospitalizations and 6,300 deaths during the 2019-2020 season.

The number of active cases also plays a role.

“You will see breakthrough infections in any vaccination when you’re vaccinating literally tens and tens and tens of millions of people,” Dr. Anthony Fauci, President Joe Biden’s medical adviser, said at a March briefing.

Finally, coronavirus vaccines are best at reducing the seriousness of the illness rather than preventing it from spreading.

About 98,000 Americans are hospitalized with COVID-19 as of Jan. 3, but that’s still below last winter’s high mark of 137,000 hospitalizations, CNBC reported. And coronavirus deaths are far below those at the height of the pandemic.

Does the omicron variant evade vaccines?

The omicron variant makes up 95% of all new COVID-19 cases in the United States, the CDC reported Saturday, Jan. 1.

The variant was first reported by researchers in South Africa on Nov. 24 after several doctors noticed symptoms among their patients that differed slightly compared to those caused by the delta variant, the dominant version of the germ spreading globally, McClatchy News reported.

Genetic sequencing revealed the variant sports a large number of mutations unseen in other variants.

Federal health officials confirmed the first omicron case in the U.S. on Dec. 1, in a fully vaccinated California resident who recently returned from South Africa, McClatchy News reported.

The variant seems to produce less severe symptoms but spreads more rapidly than other versions of the coronavirus, The Washington Post reported.

“There’s been so much talk of just saying, ‘Oh, it’s just so much less severe. It’s cold-like,’” Shaun Truelove of Johns Hopkins University told CBS News. “Sure, maybe it’s similar to some of those things in terms of severity. But this virus is so much more transmissible than all of those things.”

The variant spreads so efficiently in part because it grows especially well in the nose and upper airways, The Washington Post reported.

A Danish study suggests the omicron variant also may be better at evading vaccines, although the research has not been peer-reviewed.

Other experts say coronavirus vaccines, particularly with boosters, are effective against the omicron variant, but as with other versions of the virus they are best at reducing severity.

“The dam has broken with a milder variant,” David Rubin, director of PolicyLab at Children’s Hospital of Philadelphia, told The Washington Post. “Most people who made the correct choice to get vaccinated are protected from severe disease.”

This story was originally published January 5, 2022 at 12:08 PM with the headline "Why are vaccinated people catching COVID? It doesn’t mean vaccines aren’t working."