How long do COVID-19 vaccines last?
How long do COVID-19 vaccines last?

How long do COVID-19 vaccines last?

Even with a booster, your COVID-19 vaccine’s ability to prevent hospitalization can drop by 20% after just four months.

Sarah Tew / CNET

For the most up-to-date news and information on the coronavirus pandemic, visit WHO and CDC sites.

Messenger RNA vaccines, such as those offered by Pfizer and Moderna, offer good protection against serious COVID-19 complications – especially after a booster shot – but their potency declines faster than some had thought, according to the Centers for Disease Control and Prevention.

IN a message issued Friday, the CDC said it found that vaccine protection against hospitalization dropped markedly after just four months, even with a booster. The Agency’s research started on 26 August 2021 and ended on 22 January 2021, approximately one month after the more transmissible omicron variant overtook the delta as the more widespread mutation.

During the period when delta was prevalent, hospitalization protection was 96% within two months after a third mRNA shot. But it dropped to 76% within four months.

During the omicron wave, hospitalization protection was 91% within two months of an mRNA booster, and then dropped to 78% after 16 weeks.

Without that booster, hospitalization protection within two months of another shot was only 71% and dropped further to 54% after five months.

Here’s what we know about how long COVID vaccines stay effective and whether recommendations for a fourth shot are on the table, plus why the CDC has changed the definition of “fully vaccinated” and how to get free N95 masks.

How long do mRNA vaccines remain effective against COVID-19?

How long your vaccine stays effective depends on the strain of COVID you have been exposed to, how many shots you have received and what you are trying to prevent.

The effectiveness of COVID vaccines decreases over time, especially against potent strains such as the newer omicron variant. A December study from the UK Health Security Agency indicated protection against infection decreased by as much as 65% after just 10 weeks.

A October 2021 report published in The Lancet stated that Pfizer / BioNTech’s vaccine, Comirnaty, was 88% effective in preventing infection in the weeks following another shot. But that protection took a dive, to 47%, six months later.

Vaccination card COVID vaccine

Three shots of an mRNA vaccine provided 87% protection against an emergency room visit within the two months, but dropped to 66% after four months and 31% after nine.

Getty Images (stock)

Its ability to prevent hospitalization and death remained high at 90% for at least six months, even against the delta variant that dominated at the time It reported Reuters.

Researchers from Pfizer and Kaiser Permanente examined the health records of about 3.4 million patients between December 2020 and August 2021. They found that the vaccine efficacy against delta was 93% after the first month and then dropped to 53% after four months.

Compared to other pre-omicron variants, the effect decreased to 67% from 97%.

But the February CDC study incorporates new data on the omicron variant and booster shots: It found that vaccine protection against hospitalization when delta was dominant dropped to 76% after four months, from a maximum of 96% within two months after a booster.

Against omicron, hospitalization protection was 91% within two months of an mRNA booster, and then dropped to 78% after four months.

Protection from an emergency room visit dropped from 87% within two months of a booster to only 66% after four or five months. After another five months, it plunged to only 31% protection against an emergency room or emergency meeting.

Without that booster, hospitalization protection within two months of another shot was only 71% and dropped further to 54% after five months.

Do the new data suggest that a fourth shot is coming?

That The CDC has updated its guidelines January to indicate that immunocompromised humans could receive a fourth COVID-19 shot. Israel has already approved a fourth dose of Pfizer or Modernas mRNA vaccine for vulnerable people 18 years of age and older.

Fourth shots for seniors could also be possible in the United States: On January 22, White House Chief Medical Officer Dr. Anthony Fauci that it was “entirely conceivable” that a fourth shot would be needed.

“But before we make that decision about another boost, we will clearly determine what the durability of the protection is of the regular boost, the third shot that we are talking about,” he said. ABC this week.

Who is eligible for a fourth vaccine shot right now in the US?

In October became The CDC approved a third primary shot of an mRNA vaccine, such as Pfizers or Modernas, for people who are immunocompromised or have other specific health problems. The third shot should be fired at least 28 days after the second.

Five months after the third primary shot, vulnerable people are entitled to their booster or fourth shot.

Conditions that the CDC is considering “moderately or severely immunocompromised” includes:

  • Patients undergoing active cancer treatment for tumors or blood cancers
  • Those with organ transplants who take medication to suppress the immune system
  • Those who have received a stem cell transplant within the last two years
  • Moderate or severe immune deficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Severe HIV infection
  • Patients taking medication or medications that may suppress their immune response

Immunocompromised individuals have reported seeking the fourth shot but have been rejected by some pharmacies. This was reported by Kaiser Health News The CDC spoke with major pharmacy chains to make sure they are aware that some Americans are eligible to receive their fourth booster shot.

According to the CDC’s recommendations, patients do not have to show evidence that they are immunocompromised.

Will everyone be eligible for a fourth COVID vaccine dose in the end?

Researchers in Germany, the UK and other countries are considering the fourth shot of a COVID-19 vaccine to the general public. In January, EU health ministers were asked to prepare for the fourth dose as soon as data indicate they are needed, according to Reuters.

This year, Israel began offering fourth booster shots to citizens 60 years and older before expanding to all vulnerable adults, and Denmark approved the fourth dose for vulnerable communities.

Mikael Dolsten

Pfizer’s chief scientist Mikael Dolsten, seen here in 2017, says a fourth vaccine dose is “very likely.”

Sylvain Gaboury / Patrick McMullan via Getty Images

“With the data now coming for the omicron variant, it is very clear that our vaccine for the omicron variant must be a three-dose vaccine,” said Ugur Sahin, CEO of BioNTech, which is developing a vaccine in collaboration 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’s very likely that we’ll need a fourth booster, possibly as early as spring, especially if omicron continues to dominate,” said Mikael Dolsten, Pfizer’s chief scientific officer. told CBS News.

What has Pfizer said about a fourth booster shot to protect against COVID-19?

“I think we’ll need the fourth dose,” That’s what Pfizer chair Albert Bourla told CNBC In December. Bourla initially expected a full-year waiting period after a third dose, but with omicron, “we may need it sooner,” he said.

“There are vaccines like polio [where] one dose is enough, ” Pfizer’s Bourla said back in April. “And there are vaccines, like the flu, that you need every year. The COVID-19 virus looks more like the flu virus than the polio virus.”

Leaders said companies are experimenting with an omicron-specific version of Pfizer-BioNTech’s current vaccine, Comirnaty, which could be ready by March, pending regulatory approval.

They are also looking at a multivariate vaccine that could protect against other strains, such as the original alpha variant and more virulent delta strain.


The declining effectiveness of vaccines has made masks a continuing priority.

Sarah Tew / CNET

What has Moderna said about a fourth shot?

Like Pfizer, Moderna said it is testing the effectiveness of its COVID-19 vaccine, SpikeVax, against omicron. The company has offered few details, but said a variant-specific image could be available in early 2022.

Modern President Stephen Hoge said we will most likely need annual COVID boosters, just as we do with the flu, at least to protect against the highest risk of infection and serious illness. Moderna works on omicron-specific boosters, Hoge told Reutersbut realistically, they will not be on the market “until March and maybe more in the second quarter.”

Its current booster is a 50 microgram dose, and although the company has also reported that a 100 microgram dose of Spikevax has been shown to be exponentially effective against omicron, it does not plan to seek FDA approval for the double dose.

What did Johnson & Johnson say about another booster shot?

ONE study of 69,000 healthcare professionals published in December by the South African Medical Research Council found that for those already receiving the J&J vaccine, Ad26.COV.2, a booster given six to nine months later raised their odds of hospitalization from 63% to 85%.

The research was conducted between mid-November and mid-December 2021, with the omicron variant representing 98% of all confirmed COVID cases in South Africa, suggesting that the vaccine offers strong protection against the highly contagious strain.

“This adds to our growing body of evidence showing 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 it’s new the omicron variant is different from the delta strainwhat to know about Modern COVID booster and how to choose which booster shot you want to take.

The information 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 healthcare provider regarding any questions you may have about a medical condition or health goals.

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