All around the world, there seem to be signs that immunity to SARS-CoV-2, the coronavirus that causes the disease COVID-19, doesn't last very long after you're vaccinated.
Israel is now having one of the world's worst COVID-19 surges about five months after vaccinating a majority of its population. And in the U.S., health officials are recommending a booster shot eight months after the original vaccine course.
So, how long does immunity last after two doses of the vaccine? Six months or so? And at that point, how much protection is left over?
It all depends on which type of immunity you're talking about, says immunologist Ali Ellebedy at Washington University in St. Louis. Six months after your vaccine, your body may be more ready to fight off the coronavirus than you might think.
"If you were vaccinated six months ago, your immune system has been training for six months you are better ready to fight a COVID-19 infection," says Ellebedy.
A series of new studies, including two led by Ellebedy, suggests that mRNA vaccines like those from Pfizer-BioNTech and Moderna trigger the immune system to establish long-term protection against severe COVID-19 protection that likely will last several years or even longer, Ellebedy says.
To understand what he's talking about, let's say you received the second Moderna or Pfizer vaccine six months ago. Right away, your immune system got to work and began making antibodies.
These antibodies are a bit like archers outside the moat of a castle. They set up in the lining of your nose and throat, ready to shoot down (aka neutralize) any SARS-CoV-2 particles that try to enter the moat (aka your nasal tissue).
These antibodies can prevent an infection, says bioimmunologist Deepta Bhattacharya at the University of Arizona. They stop the virus from entering cells and setting up shop. They are the body's front-line defense.
But right after vaccination, this initial round of antibodies has a few problems. The antibodies are a bit wimpy. They're not that well trained at killing SARS-CoV-2, and they're not very durable, Bhattacharya says.
About a month after the second mRNA shot, the number of antibodies in the blood reaches its peak level and then starts to decline. The antibodies themselves degrade and the cells that make them die, a study published in the journal Nature reported in June.
This happens with every vaccine, whether it's for COVID-19, the flu or measles, Bhattacharya says. "In every single immune response, there is a sharp rise in antibodies, a period of sharp decline, and then it starts to settle into a more stable nadir."
The media has largely focused on this decline of antibodies as the cause of "waning immunity." And it's true, Bhattacharya says, that this decline in antibodies, combined with the high potency of the delta variant, which began dominating many countries this year, is likely increasing the rate of infection in fully vaccinated people.
"If you get a big dose of delta, as the variant often gives, the virus can slip past the initial wall of antibodies," he says. "So I think we may be seeing some signs of that. But the [level of breakthrough infections] is probably not as dramatic as I think it's being made out to be."
Why? Because the media has largely overlooked several key facts about the antibodies present eight months after the vaccine. For starters, they're more powerful than the original ones triggered by the vaccine, Bhattacharya says.
While the first round of archers (antibodies) was out guarding the moat of your castle (respiratory tract), the immune system wasn't just sitting around idly, hoping those soldiers would be enough. Instead, it was busy training better archers and a whole bunch of foot soldiers too.
After your second shot, the immune system sets up a training center in the lymph nodes to teach special cells how to make more powerful antibodies, the Nature paper from June reported.
"The quality of the antibody improves over time. It takes far fewer of those new antibodies to protect you," Bhattacharya says. "So I think that worrying about antibody decline is not something that's productive," he adds.
At the same time, the cells that make these souped-up antibodies become souped up themselves, he adds. In the training center, they learn how to make a huge amount of the highly powerful antibodies.
"These cells are remarkable," Bhattacharya says. "They're estimated to spit out something like 10,000 antibody molecules per second." So you don't need many of these cells to protect you against a future infection.
"We've done some back-of-the-envelope calculations to figure out how many of these cells are needed to protect a mouse from a lethal infection. It's three," Bhattacharya says. "Of course, we're bigger than mice. But you get the sense that it doesn't take many to offer good protection."
On top of that, these cells learn something remarkable in the training center: how to persist. "They're essentially given the gift of eternity," says immunologist Ellebedy.
He and his colleagues have found that by about six months after vaccination, these antibody-producing cells go into the bone marrow, where they can live for decades, perhaps even a lifetime, studies have found, and continue to produce antibodies the entire time. In one 2008 study, researchers identified antibodies that could neutralize the 1918 flu in the blood of people who were exposed to the virus 90 years earlier.
"We looked in the bone marrow and have seen these cells in people previously infected with SARS-CoV-2," Ellebedy says. "Now we are finishing research that shows these cells appear in the bone marrow after vaccination as well."
Called long-lived plasma cells, these cells will likely pump out antibodies into the blood for decades, Ellebedy says, giving people some sustained, long-term protection against SARS-CoV-2. (There is a caveat: If the virus changes too much, these antibodies won't be as effective.)
"The antibodies are maintained at very low levels, but they're the first line of defense against an infection," Ellebedy says. "If you're taken by surprise by SARS-CoV-2, these antibodies will slow down the replication of the virus" until reinforcements come along.
And reinforcements will likely come!
On top of training up better archers (antibodies) and factories to create them (plasma cells), the immune system has also been training up the equivalent of foot soldiers, several studies have found. These foot soldiers are called memory B cells and memory T cells, and they largely serve as a surveillance system, looking for other cells infected with SARS-CoV-2.
"They're patrolling all over," Ellebedy says, checking to see if a cell has SARS-CoV-2 hiding in it. "It's almost like going through the neighborhood, house by house, and just making sure it's clean."
These foot soldiers can't prevent an infection from initially occurring, but they can quickly stop one once it occurs, says immunologist Jennifer Gommerman at the University of Toronto. "Because of the vaccine-generated 'memory' of the SARS-CoV-2 spike protein, you get a very brisk cellular immune response."
OK. So now we've got all the information to understand what's going on with the COVID-19 vaccine and immune durability.
About six months after the shots, the antibodies in the blood have fallen as expected. They're also a bit less effective against the delta variant. "Together, that means there are more symptomatic infections as we go further out from the vaccination rollout," Gommerman says.
But in vaccinated people, these infections will most likely be mild or moderate because the immune system isn't starting from scratch. In fact, it's the opposite. It has been training cells and antibodies for months.
"You still have all this immunity inside of your body that will then say, 'OK, we've had a breach, and it's time to bring in the cellular immunity and respond to this threat,' " Gommerman says. "And because of vaccination, you have cells that can do that really quickly."
And so, overall, you'll be less sick than if you weren't vaccinated and be much less likely to end up in the hospital, she says.
"That's really what the vaccines were designed to do to teach the immune system to deal with this invader if an infection does occur," Gommerman says. "And the vaccines do that remarkably well."
Go here to see the original:
How Long Does Immunity To COVID-19 Last? : Goats and Soda - NPR
- As 2024 Travel Hits Pre-Covid Levels, Here's When To Go To Europe - Forbes - March 10th, 2024 [March 10th, 2024]
- Comparison of Impressions of COVID-19 Vaccinations Stratified by the Number of Vaccinations Among Japanese ... - Cureus - March 10th, 2024 [March 10th, 2024]
- Effect of the COVID-19 pandemic on mental health visits in primary care: an interrupted time series analysis from nine ... - The Lancet - March 10th, 2024 [March 10th, 2024]
- Faith and rehab keep Southwick woman on path to recovery from COVID - MassLive.com - March 10th, 2024 [March 10th, 2024]
- China to draw on Covid-19 experience to tackle future pandemics - theSun - March 10th, 2024 [March 10th, 2024]
- Free COVID tests through USPS are ending todayhere's where to get tests online - Reviewed - March 10th, 2024 [March 10th, 2024]
- Concern about COVID reaches record low across political spectrum: Survey - The Hill - March 10th, 2024 [March 10th, 2024]
- He Had 217 Covid Shots Without Side Effects, Study Finds - The New York Times - March 10th, 2024 [March 10th, 2024]
- A Man Got 217 COVID-19 Vaccines. Here's What Happened - TIME - March 10th, 2024 [March 10th, 2024]
- German man vaccinated 217 times against covid with no ill effects - The Washington Post - March 10th, 2024 [March 10th, 2024]
- Andrew Cuomo Faces House Subpoena Over Covid Deaths in Nursing Homes - The New York Times - March 10th, 2024 [March 10th, 2024]
- It's been 4 years since COVID hit Michigan. For Long COVID patients, the pandemic isn't over. Michigan Advance - Michigan Advance - March 10th, 2024 [March 10th, 2024]
- 4th Anniversary of the Covid-19 Pandemic - erienewsnow.com - March 10th, 2024 [March 10th, 2024]
- Reflecting on 4 years of the COVID-19 pandemic and discussing what's to come - WBUR News - March 10th, 2024 [March 10th, 2024]
- CDC shortens 5-day COVID isolation, updates guidance on masks and testing in new 2024 recommendations - CBS News - March 10th, 2024 [March 10th, 2024]
- Father, daughter convicted in fraud related to COVID-19 relief - The Cincinnati Enquirer - February 7th, 2024 [February 7th, 2024]
- Supreme Court to weigh whether Covid misinformation is protected speech - STAT - February 7th, 2024 [February 7th, 2024]
- Oklahoma leads country in long Covid - 2 News Oklahoma KJRH Tulsa - February 7th, 2024 [February 7th, 2024]
- MCFR firefighter dies after battle with COVID-19 - WCJB - February 7th, 2024 [February 7th, 2024]
- Audio-based AI classifiers show no evidence of improved COVID-19 screening over simple symptoms checkers - Nature.com - February 7th, 2024 [February 7th, 2024]
- Hidden death toll of COVID-19 pandemic revealed - Earth.com - February 7th, 2024 [February 7th, 2024]
- Switching arms improves effectiveness of two-dose vaccinations, OHSU study suggests - OHSU News - February 7th, 2024 [February 7th, 2024]
- Tributes paid to Irish health official 'central' to EU Covid-19 response - The Irish Times - February 7th, 2024 [February 7th, 2024]
- Court: Not wearing mask during COVID-19 health emergency isn't protected speech - Honolulu Star-Advertiser - February 7th, 2024 [February 7th, 2024]
- One arm or two? How you get vaccinated may make a difference - The Seattle Times - February 7th, 2024 [February 7th, 2024]
- 70% of kindergarteners didn't pass readiness test in pandemic, study estimates - University of Minnesota Twin Cities - February 7th, 2024 [February 7th, 2024]
- USS Theodore Roosevelt sailors roam free on Guam for first time since COVID-19 outbreak - Stars and Stripes - February 7th, 2024 [February 7th, 2024]
- Pandemic linked to 14% increase in underweight children in India - Medical Xpress - February 7th, 2024 [February 7th, 2024]
- COVID and travel: Should I still wear a mask on the plane? - USA TODAY - February 7th, 2024 [February 7th, 2024]
- Vaccine hesitancy and equity: lessons learned from the past and how they affect the COVID-19 countermeasure in ... - Globalization and Health - February 7th, 2024 [February 7th, 2024]
- Increase in STIs Among Adolescents Witnessed During COVID-19 Pandemic - Drug Topics - February 7th, 2024 [February 7th, 2024]
- VDH: COVID deaths not seeing decline - Vermont Biz - February 7th, 2024 [February 7th, 2024]
- US outpatient care for serious mental health issues declined during COVID-19 - University of Minnesota Twin Cities - February 7th, 2024 [February 7th, 2024]
- COVID-19 Vaccination in a Patient With Gluten Enteropathy: A Case Report - Cureus - February 7th, 2024 [February 7th, 2024]
- COVID-19 cases drop, but still lots of flu, RSV cases in Erie County - GoErie.com - February 7th, 2024 [February 7th, 2024]
- Lives versus livelihoods: The COVID-19 trade-off from an epidemiological-economic perspective - CEPR - February 7th, 2024 [February 7th, 2024]
- Weatherhead's Jonathan Ernest notes economic changes of childcare facilities following COVID-19 pandemic - The Daily | Case Western Reserve University - February 7th, 2024 [February 7th, 2024]
- U.S. adults face distress, unequal mental health care access during the COVID-19 era - News-Medical.Net - February 7th, 2024 [February 7th, 2024]
- Simnotrelvir to reduces the symptoms of mild to moderate COVID-19 - 2 Minute Medicine - February 7th, 2024 [February 7th, 2024]
- Vaccine Effectiveness: Which COVID-19 Shots Offer the Most Protection? - SciTechDaily - February 7th, 2024 [February 7th, 2024]
- New evidence confirms COVID-19 vaccination in pregnancy is safe for babies - Gavi, the Vaccine Alliance - February 7th, 2024 [February 7th, 2024]
- Audit Committee co-chairs, Evers at odds over interest from COVID-19 funds - WisPolitics.com - February 7th, 2024 [February 7th, 2024]
- Evaluation of Olfactory Dysfunction Among COVID-19 Patients in Baghdad, Iraq - Cureus - February 7th, 2024 [February 7th, 2024]
- COVID-19's impact on early education: Retrospective study shows decrease in kindergarten readiness - News-Medical.Net - February 7th, 2024 [February 7th, 2024]
- Rutgers researchers work on breakthrough COVID-19 treatment | Video - NJ Spotlight News - February 7th, 2024 [February 7th, 2024]
- Curious Iowa: Has the state spent all of its COVID-19 relief funding? - The Gazette - October 16th, 2023 [October 16th, 2023]
- Accelerating into Immunization Agenda 2030 with momentum from ... - Infectious Diseases of Poverty - BioMed Central - October 16th, 2023 [October 16th, 2023]
- Study Uncovers Why Young Children Suffer Less Severe COVID-19 - Technology Networks - October 16th, 2023 [October 16th, 2023]
- Wenstrup, Select Subcommittee Majority Members Investigate ... - House Committee on Oversight and Reform | - October 16th, 2023 [October 16th, 2023]
- With COVID-19 emergency orders lifted, employers seek guidance ... - Hartford Business Journal - October 16th, 2023 [October 16th, 2023]
- Computer-aided diagnosis of chest X-ray for COVID-19 diagnosis in ... - Nature.com - October 16th, 2023 [October 16th, 2023]
- Maternal COVID-19 Vaccination, Infection Boosts Infant Antibody ... - Contagionlive.com - October 16th, 2023 [October 16th, 2023]
- Three Middlesex County Individuals Admit COVID-19 Fraud ... - Department of Justice - October 16th, 2023 [October 16th, 2023]
- Seventeen Broward Sheriff's Office Employees Charged with COVID ... - Department of Justice - October 16th, 2023 [October 16th, 2023]
- New COVID-19 Booster and Flu Shot Available at Select Public ... - Mecklenburg County (.gov) - October 16th, 2023 [October 16th, 2023]
- Ban on COVID vaccine mandates by private businesses, including ... - The Texas Tribune - October 16th, 2023 [October 16th, 2023]
- What Are the Side Effects of the 2023 COVID Vaccine? Experts ... - Good Housekeeping - October 16th, 2023 [October 16th, 2023]
- Covid inquiry: Bereaved families relief as High Court dismisses Cabinet Office JR - openDemocracy - July 6th, 2023 [July 6th, 2023]
- UK health agency failed to account for 3.3bn of Covid inventory, say MPs - Financial Times - July 6th, 2023 [July 6th, 2023]
- COVID-19 Working Paper: Obesity Prevalence Among U.S. Adult ... - usda.gov - July 6th, 2023 [July 6th, 2023]
- California Changes Definition of COVID-19 Outbreak Easing the ... - Fisher Phillips - July 6th, 2023 [July 6th, 2023]
- New Study Shows Robust Pandemic Preparedness Strongly Linked ... - Nuclear Threat Initiative - July 6th, 2023 [July 6th, 2023]
- COVID-19 Infection Reduces the Risk of UTIs, Bacteremia, and ... - Contagionlive.com - July 6th, 2023 [July 6th, 2023]
- Europe Phases Out COVID-19 Flexible Regulations - Pharmaceutical Technology Magazine - July 6th, 2023 [July 6th, 2023]
- Travel Pains and COVID: How to Decide if You're Ready to Travel - CreakyJoints - July 6th, 2023 [July 6th, 2023]
- COVID Depression and Anxiety | Johns Hopkins Medicine - April 17th, 2023 [April 17th, 2023]
- Man declared dead due to Covid found 'shockingly' alive after 2 years in MP - Hindustan Times - April 17th, 2023 [April 17th, 2023]
- Senate votes to end Covid-19 emergency, 3 years after initial declaration - CNN - March 31st, 2023 [March 31st, 2023]
- DC COVID-19 centers closing Friday: Here's what you need to know - WJLA - March 31st, 2023 [March 31st, 2023]
- Can grade retention help with COVID-19 learning recovery in schools? - Brookings Institution - March 28th, 2023 [March 28th, 2023]
- On 3-year anniversary of COVID-19 in NC, Winston-Salem woman shares story of loss and healing after losing 2 loved ones - WXII12 Winston-Salem - March 4th, 2023 [March 4th, 2023]
- Oregon, Washington will lift mask requirements in health care settings on April 3 - KATU - March 4th, 2023 [March 4th, 2023]
- WHO says all theories for COVID origin 'remain on table' as lab leak theory gains traction - Sky News - March 4th, 2023 [March 4th, 2023]
- New COVID-19 omicron subvariant XBB.1.5 sweeping the nation, making up majority of cases - ABC Action News Tampa Bay - February 15th, 2023 [February 15th, 2023]
- Man gets 21 years in prison for stabbing wife in the Ozarks over COVID-19 stimulus check and their children - Law & Crime - February 15th, 2023 [February 15th, 2023]
- Healthline: Medical information and health advice you can trust. - January 2nd, 2023 [January 2nd, 2023]
- China can expect repeat Covid infections with new strains on the way: experts - South China Morning Post - January 2nd, 2023 [January 2nd, 2023]
- PCR tests for travellers reintroduced around the world as Covid-19 cases surge - The National - January 2nd, 2023 [January 2nd, 2023]
- Covid-19 surge after Covid-19 surge has made it impossible for US hospitals to plan for the future - Vox.com - January 2nd, 2023 [January 2nd, 2023]
- COVID-19 in China: Demand for a particular fruit rises as people seek natural remedies to fight the virus - WION - December 21st, 2022 [December 21st, 2022]