As protection from COVID boosters wanes, US health officials plan for a fourth vaccine shot.
Clifford is a managing editor at CNET. He spent a handful of years at Peachpit Press, editing books on everything from the first iPhone to Python. He also worked at a handful of now-dead computer magazines, including MacWEEK and MacUser. Unrelated, he roots for the Oakland A’s.
Dan is a writer on CNET’s How-To team. His byline has appeared in Newsweek, NBC News, The New York Times, Architectural Digest, The Daily Mail and elsewhere. He is a crossword junkie and is interested in the intersection of tech and marginalized communities.
How To and Money writer
I’m a writer/editor for CNET How-To and Money, living in South Berkeley, CA with two kids and two cats. I enjoy a variety of games and sports — particularly poker, ping-pong, disc golf, basketball, baseball, puzzles and independent video games.
Less than half of fully vaccinated Americans have received a third shot.
As COVID vaccine data demonstrates decreased protection over time, US and world health regulators are considering the options for introducing an additional booster shot — or fourth vaccine dose — to the general population. The Wall Street Journal reported Saturday that the FDA is potentially preparing to authorize a fourth booster shot in fall 2022, according to “people familiar with the matter.”
In a press briefing Wednesday, White House Chief Medical Adviser Dr. Anthony Fauci said, “The potential future requirement for an additional boost or a fourth shot for mRNA or a third shot for J&J is being very carefully monitored in real time.”
Messenger RNA vaccines, like the ones offered by Pfizer and Moderna, offer good protection against serious COVID-19 complications — especially after a booster shot — but their potency wanes over time.
In its latest weekly report, the CDC announced that protection against hospitalization from mRNA vaccines dropped noticeably after just four months, even with a booster. In the period when delta was predominant, protection against hospitalization was 96% within two months of a third mRNA shot. But it sank to 76% within four months.
During the omicron wave, protection from hospitalization fell from 91% within two months of an mRNA booster to 78% after 16 weeks.
Read on to learn what we know about how long COVID vaccines remain effective and when a fourth shot could be approved.
For more, read , learn why and get the latest on shifting .
How long your vaccine remains effective depends on the strain of COVID you’ve been exposed to, how many shots you’ve received and what you’re trying to prevent.
The effectiveness of COVID vaccines decreases over time, especially against potent strains like the newer omicron variant. One December study from the UK’s Health Security Agency indicated protection from infection waned as much as 65% after just 10 weeks.
An October 2021 report published in The Lancet determined Pfizer/BioNTech’s vaccine, Comirnaty, was 88% percent effective in preventing infection in the weeks following a second shot. But that protection took a nosedive, to 47%, six months later.
Three shots of an mRNA vaccine provided 87% protection against an ER visit within the two months, but fell to 66% after four months, and 31% after nine.
Its ability to prevent hospitalization and death remained high at 90% for at least six months, even against the delta variant dominant at the time, Reuters reported.
Researchers from Pfizer and Kaiser Permanente studied the health records of roughly 3.4 million patients between December 2020 and August 2021. They found vaccine effectiveness against delta was 93% after the first month and then declined to 53% after four months.
Against other pre-omicron variants, efficacy declined to 67% from 97%.
But the February CDC study incorporates new data on the omicron variant and booster shots: It found that the vaccines’ protection against hospitalization when delta was dominant dropped to 76% after four months, from a high of 96% within two months of a booster.
Against omicron, protection from hospitalization was 91% within two months of an mRNA booster, then dropped to 78% after four months.
Protection from an ER visit slipped from 87% within two months of a booster to just 66% after four or five months. After another five months, it plummeted to just 31% protection against an ER or urgent-care encounter.
Without that booster, protection against hospitalization within two months of a second shot was only 71% and fell further to 54% after five months.
The CDC updated its guidance in January to indicate that immunocompromised people could receive a fourth COVID-19 shot. Israel has already approved a fourth dose of Pfizer or Moderna’s mRNA vaccine for vulnerable people 18 and older. Sweden has also authorized citizens over 80 to get a fourth shot, starting Feb. 22.
Throughout the omicron wave, Fauci has stressed the importance of thoroughly evaluating the data on third booster shots before making a decision on a fourth dose. In a January interview, he said, “before we make that decision about yet again another boost, we want to determine clearly what the durability of protection is of that regular boost, that third shot that we’re talking about.”
As more data on booster protection indicates waning protection, the FDA is making decisions on who will be eligible for a fourth shot, when those additional boosters will be offered and whether the extra shot will be specific to omicron.
According to the Wall Street Journal, regulators are leaning toward a fall 2022 authorization of additional mRNA vaccine boosters. One idea is to synchronize the new COVID shots with the timing of the existing yearly influenza vaccine in order to increase reception.
In October, the of an mRNA vaccine, like Pfizer’s or Moderna’s, for individuals who are immunocompromised or have other specific health issues. The third shot should be delivered at least 28 days after the second.
Five months after that third primary shot, vulnerable people are eligible for their booster, or fourth shot.
Conditions that the CDC considers “moderately or severely immunocompromised” include:
Our Health & Wellness newsletter puts the best products, updates and advice in your inbox.
Immunocompromised people have reported seeking fourth shots but being turned away by some pharmacies. Kaiser Health News reported the CDC spoke with major pharmacy chains to ensure they are aware of the eligibility of some Americans to receive their fourth booster shot.
According to the CDC’s recommendations, patients do not need to show proof that they are immunocompromised.
Scientists in Germany, the UK and other countries are considering fourth shots of a COVID-19 vaccine for the general public.In January, health ministers in European Union countries were told to prepare for fourth doses as soon as data indicates they are needed, according to Reuters.
This year, Israel started offering fourth booster shots to citizens 60 and older before expanding to all vulnerable adults, and Denmark authorized fourth doses for at-risk communities. Sweden recently authorized fourth doses of the mRNA vaccines for all citizens over 80, starting Feb. 22.
Pfizer chief scientific officer Mikael Dolsten, seen here in 2017, says a fourth vaccine dose is “very likely.”
“With the data now coming for the omicron variant, it is very clear our vaccine for the omicron variant should be a three-dose vaccine,” Ugur Sahin, CEO of BioNTech, which makes a vaccine in partnership with Pfizer, said in a statement.
If three doses of the Pfizer COVID-19 vaccine are needed to protect against omicron, the timeline for a fourth shot could be pushed up to as early as March, Pfizer executives said.
“I think it is very likely that we will need a fourth booster, possibly already this spring, particularly if omicron continues to dominate,” Mikael Dolsten, Pfizer’s chief scientific officer, told CBS News.
“I think we will need the fourth dose,” Pfizer chair Albert Bourla told CNBC in December. Bourla initially projected a waiting period of a full year after a third dose but, with omicron, “we may need it faster,” he said.
“There are vaccines like polio [where] one dose is enough,” Pfizer’s Bourla said back in April. “And there are vaccines, like flu, that you need every year. The COVID-19 virus looks more like the influenza virus than the poliovirus.”
Executives said the companies are experimenting with an omicron-specific version of Pfizer-BioNTech’s current vaccine, Comirnaty, that could be ready by March, pending regulatory approval.
They’re also looking at a multivariate vaccine that could protect against other strains, such the original alpha variant and more virulent delta strain.
The declining effectiveness of vaccines has made masks a continued priority.
Like Pfizer, Moderna said it’s testing the effectiveness of its COVID-19 vaccine, SpikeVax, against omicron. The company has offered little specifics but said a variant-specific shot could be available in early 2022.
Moderna President Stephen Hoge said we’ll most likely need annual COVID boosters, much like we do with the flu, at least to protect against the highest risk of infection and serious illness. Moderna is working on omicron-specific boosters, Hoge told Reuters, but realistically they won’t be on the market “before March and maybe more in the second quarter.”
Its current booster is a 50-microgram dose, and while the company has also reported a 100-microgram dose of Spikevax has proven exponentially effective against omicron, it does not plan to seek approval from the FDA for the double-dose.
A released in December by the South African Medical Research Council found that, for those who already received the J&J vaccine, Ad26.COV.2, a booster given six to nine months later raised their odds against hospitalization from 63% to 85%.
The research was conducted between mid-November and mid-December 2021, when the omicron variant represented 98% of all confirmed COVID cases in South Africa, suggesting the vaccine offers strong protection against the highly contagious strain.
“This adds to our growing body of evidence which shows that the effectiveness of the Johnson & Johnson COVID-19 vaccine remains strong and stable over time, including against circulating variants such as omicron and delta,” Dr. Mathai Mammen, global head of Janssen Research & Development, a pharmaceutical subsidiary of Johnson & Johnson, said in a statement.
For more on COVID-19, here’s how the new , what to know about the and how to .
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.