Is Vaccine Immunity Waning?

Late last month, researchers in Israel released some alarming new Covid-19 data. The data showed that many Israelis who had been among the first to receive the vaccine were nonetheless catching the Covid virus. Israelis who had been vaccinated later were not getting infected as often.

The study led to headlines around the world about waning immunity — the idea that vaccines lose their effectiveness over time. In the U.S., the Israeli study accelerated a debate about vaccine booster shots and played a role in the Biden administration’s recent recommendation that all Americans receive a booster shot eight months after their second dose.

But the real story about waning immunity is more complex than the initial headlines suggested. Some scientists believe that the Israeli data was misleading and that U.S. policy on booster shots has gotten ahead of the facts. The evidence for waning immunity is murky, these scientists say, and booster shots may not have a big effect.

After returning from an August break last week, I have spent time reaching out to scientists to ask for their help in understanding the current, confusing stage of the pandemic. How worried should vaccinated people be about the Delta variant? How much risk do children face? Which parts of the Covid story are being overhyped, and which deserve more attention?

I will be trying to answer these questions in the coming weeks. (I’d also like to know what questions you want answered; submit them here.)

One of the main messages I’m hearing from the experts is that conventional wisdom about waning immunity is problematic. Yes, the immunity from the Covid vaccines will wane at some point. But it may not yet have waned in a meaningful way.

“There’s a big difference between needing another shot every six months versus every five years,” Dr. David Dowdy, an epidemiologist at Johns Hopkins University, told me. “So far, looking at the data we have, I’m not seeing much evidence that we’ve reached that point yet.”

Simpson strikes again

At first glance, the Israeli data seems straightforward: People who had been vaccinated in the winter were more likely to contract the virus this summer than people who had been vaccinated in the spring.

Yet it would truly be proof of waning immunity only if the two groups — the winter and spring vaccine recipients — were otherwise similar to each other. If not, the other differences between them might be the real reason for the gap in the Covid rates.

As it turns out, the two groups were different. The first Israelis to have received the vaccine tended to be more affluent and educated. By coincidence, these same groups later were among the first exposed to the Delta variant, perhaps because they were more likely to travel. Their higher infection rate may have stemmed from the new risks they were taking, not any change in their vaccine protection.

Statisticians have a name for this possibility — when topline statistics point to a false conclusion that disappears when you examine subgroups. It’s called Simpson’s Paradox.

This paradox may also explain some of the U.S. data that the C.D.C. has cited to justify booster shots. Many Americans began to resume more indoor activities this spring. That more were getting Covid may reflect their newfound Covid exposure (as well as the arrival of Delta), rather than any waning of immunity over time.

‘Where is it?’

Sure enough, other data supports the notion that vaccine immunity is not waning much.

The ratio of positive Covid tests among older adults and children, for example, does not seem to be changing, Dowdy notes. If waning immunity were a major problem, we should expect to see a faster rise in Covid cases among older people (who were among the first to receive shots). And even the Israeli analysis showed that the vaccines continued to prevent serious Covid illness at essentially the same rate as before.

“If there’s data proving the need for boosters, where is it?” Zeynep Tufekci, the sociologist and Times columnist, has written.

Part of the problem is that the waning-immunity story line is irresistible to many people. The vaccine makers — Pfizer, Moderna and others — have an incentive to promote it, because booster shots will bring them big profits. The C.D.C. and F.D.A., for their part, have a history of extreme caution, even when it harms public health. We in the media tend to suffer from bad-news bias. And many Americans are so understandably frightened by Covid that they pay more attention to alarming signs than reassuring ones.

The bottom line

Here’s my best attempt to give you an objective summary of the evidence, free from alarmism — and acknowledging uncertainty:

Immunity does probably wane modestly within the first year of receiving a shot. For this reason, booster shots make sense for vulnerable people, many experts believe. As Dr. Céline Gounder of Bellevue Hospital Center told my colleague Apoorva Mandavilli, the C.D.C.’s data “support giving additional doses of vaccine to highly immunocompromised persons and nursing home residents, not to the general public.”

The current booster shots may do little good for most people. The vaccines continue to provide excellent protection against illness (as opposed to merely a positive Covid test). People will eventually need boosters, but it may make more sense to wait for one specifically designed to combat a variant. “We don’t know whether a non-Delta booster would improve protection against Delta,” Dr. Aaron Richterman of the University of Pennsylvania told me.

A national policy of frequent booster shots has significant costs, financially and otherwise. Among other things, the exaggerated discussion of waning immunity contributes to vaccine skepticism.

While Americans are focusing on booster shots, other policies may do much more to beat back Covid, including more vaccine mandates in the U.S.; a more rapid push to vaccinate the world (and prevent other variants from taking root); and an accelerated F.D.A. study of vaccines for children.

As always, we should be open to changing our minds as we get new evidence. As Richterman puts it, “We have time to gather the appropriate evidence before rushing into boosters.”


Hurricane Ida

Hurricane Ida wiped out power for almost a million people, including most of New Orleans. At least one person died.

The storm made landfall on the Louisiana coast yesterday, on the 16th anniversary of Hurricane Katrina.

Follow Ida’s path and updates on the damage.

The prospect of “another Katrina” has haunted New Orleans. “I just have a really eerie feeling about this one,” one resident said.

Ida quickly strengthened into a monster. Climate change is part of the reason.


A U.S. drone strike blew up a vehicle that officials said was an “imminent ISIS-K threat” to Kabul’s airport. Afghans said the strike killed as many as nine civilians, including children.

The airlift of Afghans fleeing Taliban rule has shut down. Britain withdrew its last troops yesterday.

With one day left until President Biden’s deadline for withdrawal, about 300 U.S. citizens who want to leave remain in Afghanistan.

Biden met with the families of the 13 U.S. soldiers killed in last week’s suicide bombing in Kabul.

The U.S. and 97 other countries said they would accept Afghan refugees.

Other Big Stories

The U.S. saw an average of 100,000 daily Covid hospitalizations over the past week for the first time since winter.

At birth, she had a case file. At 7, Julissia Batties was dead. A child welfare system meant to protect her from an abusive home life failed the ultimate test.

A Connecticut woman has to spend a week in jail for walking on the thermal grounds at Yellowstone National Park.


Gail Collins and Bret Stephens discuss Afghanistan and Biden’s domestic agenda.


Tokyo Paralympics: After years of pain, Morgan Stickney is closer to a world record than ever.

Art and life: How to paint 50,000 miles of (straight) lines.

The Media Equation: Welcome to Politico’s billion-dollar drama.

Advice from Wirecutter: Move your home office outside.

Quiz time: The average score on our most recent news quiz was 6.3. Can you do better?

Lives Lived: Ed Asner won five Emmy Awards portraying the gruff but lovable newsman Lou Grant. He died at 91.


TikTok stars on a bigger screen

For 14 years, the Kardashians ruled the genre of reality shows documenting famous families. When their program ended this summer, it left a gap in the TV landscape — one that the D’Amelios, TikTok’s most famous family, want to fill with an upcoming documentary series on Hulu.

Charli D’Amelio, 17, is the most popular person on TikTok, with 123 million followers. She’s sold signature drinks at Dunkin’ and has appeared in Super Bowl commercials. Her sister Dixie, 20, and their parents also have large followings.

Sara Reddy, the showrunner, who had previously worked on “Toddlers and Tiaras,” said she wasn’t familiar with the family when she was first pitched them as subjects. “I’m not a teenager. I really found it easy to roll my eyes at social media during Covid,” she told The Times. “Then I dug in, and what really struck me was I felt like the family was a living social experiment.” She added, “I came into their life right as fame was changing for them.” — Sanam Yar, a Morning writer


What to Cook

Make one-pot orzo with tomatoes, corn and zucchini.

What to Watch

Why are Steve Martin, Selena Gomez and Martin Short working together? It’s a mystery.

What to Read

Nineteen new books to look forward to this September, including works by Colson Whitehead, Sally Rooney and more.

Now Time to Play

The pangram from Friday’s Spelling Bee was mahogany. Here is today’s puzzle — or you can play online.

Here’s today’s Mini Crossword, and a clue: Foe (five letters).

If you’re in the mood to play more, find all of our games here.

Thanks for spending part of your morning with The Times. See you tomorrow. — David

P.S. Kathy Ryan and Maureen Dowd capture The Times’s deserted New York newsroom.

Here’s today’s print front page.

“The Daily” is about California’s recall election. On the Book Review podcast, A.O. Scott discusses William Maxwell.

Claire Moses, Ian Prasad Philbrick, Tom Wright-Piersanti and Sanam Yar contributed to The Morning. You can reach the team at [email protected].

Sign up here to get this newsletter in your inbox.

Source: Read Full Article