Could COVID-19 immunity last decades? Here’s the science.

The body builds a protective fleet of immune cells when infected with COVID-19, and in many people, those defenses linger for more than six months after the infection clears, according to a new study.

The immune cells appear so stable, in fact, that immunity to the virus may last at least several years, the study authors said. “That amount of [immune] memory would likely prevent the vast majority of people from getting hospitalized disease, severe disease, for many years,” co-author Shane Crotty, a virologist at the La Jolla Institute of Immunology in California, told The New York Times, which first reported on the study.

That said, making predictions about how long immunity to the coronavirus lasts can be “tricky,” Nicolas Vabret, an assistant professor of medicine at the Mount Sinai Icahn School of Medicine, who was not involved in the study, told Live Science.

“It would be surprising to see the … immune cells build up in patients over six months and suddenly crash after one year,” Vabret said in an email. But “the only way to know whether SARS-CoV-2 immunity will last decades is to study the patients over the same period of time.” 

In other words, we won’t know exactly how long immunity lasts without continuing to study those who have recovered from COVID-19. However, the new study, posted Nov. 16 to the preprint database bioRxiv, does provide strong hints that the protection is long-lived — although clearly not in all people, as there have been several cases of individuals being reinfected with the coronavirus after recovering. 

The research dives into the ranks of the human immune system, assessing how different lines of defense change after a COVID-19 infection. 

These defenses include antibodies, which bind to the virus and either summon immune cells to destroy the bug or neutralize it themselves. Memory B cells, a kind of white blood cell, “remember” the virus after an infection clears and help quickly raise the body’s defenses, should the body be reexposed. Memory T cells, another kind of white blood cell, also learn to recognize the coronavirus and dispose of infected cells. Specifically, the authors looked at T cells called CD8+ and CD4+ cells.

The authors assessed all these immune cells and antibodies in 185 people who had recovered from COVID-19. A small number of participants never developed symptoms of the illness, but most experienced mild infections that did not require hospitalization. And 7% of the participants were hospitalized for severe disease. 

The majority of participants provided one blood sample, sometime between six days and eight months after the onset of their infections. Thirty-eight participants gave several blood samples between those time points, allowing the authors to track their immune response through time.

Ultimately, “one could argue that what they found is not so surprising, as the immune response dynamics they measure look like what you would expect from functioning immune systems,” Vabret said. 

The authors found that antibodies specific to the spike protein — a structure on the surface of the virus — remain stable for months and begin to wane about six to eight months after infection. At five months post-infection, nearly all the participants still carried antibodies. The volume of these antibodies differed widely between people, though, with an up to 200-fold difference between individuals. Antibody counts normally fall after an acute infection, Vabret noted, so the modest drop-off at six to eight months came as no surprise.

By comparison, memory T and B cells that recognize the virus appear extremely stable, the authors noted. “Essentially no decay of … memory B cells was observed between days 50 and 240,” or eight months later, Marc Jenkins, an immunologist at the University of Minnesota Medical School, who was not involved in the study, said in an email.

“Although some decay of memory T cells was observed, the decay was very slow and may flatten out at some point,” Jenkins added. There’s reason to believe that the number of memory T cells may stabilize sometime after infection, because T cells against a related coronavirus, SARS-CoV, have been found in recovered patients up to 17 years later, according to a study published July 15 in the journal Nature

Early in the pandemic, scientists raised concerns that immunity to the virus may wear off in about a year; this trend can be seen with the four coronaviruses that cause the common cold, Live Science previously reported. However, studies suggest that the body’s reaction to common coronaviruses may differ from that to viruses like SAR-CoV and SARS-CoV-2, which hopped from animals to humans. 

“We don’t really know why seasonal coronaviruses do not induce lasting protective immunity,” Vabret said. But the new study, along with other recent evidence, suggests that SARS-CoV-2 immunity may be more robust, said Jason Cyster, a professor of microbiology and immunology at the University of California, San Francisco, who was not involved in the study.

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That said, a few participants in the new study did not mount long-lasting immune responses to the novel virus. Their transient responses may come down to differences in how much virus they were initially exposed to, or genetics may explain the difference, Cyster said. For instance, genes known as human leukocyte antigen (HLA) genes differ widely between individuals and help alert the immune system to foreign invaders, Live Science previously reported

These inherent differences between people may help explain cases of COVID-19 reinfection, which have been relatively rare but are increasing in number, Science Magazine reported.

Again, to really understand how long COVID-19 immunity lasts, scientists need to continue to study recovered patients. “Certainly, we need to look six months down the road,” and see whether the T and B cell counts remain high, Cyster said.

Should immunity be long-term, one big question is whether that durability carries over to vaccines. But natural immunity and vaccine-generated immunity cannot be directly compared, Vabret noted. 

“The mechanisms by which vaccines induce immunity are not necessarily the same as the ones resulting from natural infection,” Vabret said. “So the immune protection resulting from a vaccine could last longer or shorter than the one resulting from natural infection.”

For example, the Pfizer and Moderna vaccines use a molecular messenger called mRNA to train the body to recognize and attack the coronavirus. No mRNA-based vaccine has ever been approved before, so “we practically know nothing about the durability of those responses,” Cyster said.

“I think [that’s] the big unknown for me, among the many,” he said.

But while some unanswered questions remain, the main takeaway from the new study is that “immune memory to SARS-CoV-2 is very stable,” Jenkins said. And — fingers crossed — perhaps those hopeful results will hold well into the future.

Originally published on Live Science. 

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It may be possible to reverse key markers of aging with a therapy used by astronauts and deep-sea divers

hyperbaric oxygen therapy

  • A specialized form of oxygen therapy appears to reverse some biological markers of aging, according to a small new study. 
  • After receiving the treatment, participants had significantly longer telomeres, the part of the chromosome that typically shortens as we age. Shorter telomeres are linked to diseases like dementia and cancer. 
  • While this is the first evidence that human telomeres can be lengthened through treatment, more research is needed to better understand what that means for chronic illness and longevity. 
  • Visit Insider's homepage for more stories.

Aging, the slow decline of function over time, is considered to be an inevitable fact of the human condition. As cells divide and reproduce in our bodies, they gradually deteriorate, and our mental and physical health declines as a result. 

But there may be a way to not only delay that cellular degeneration, but reverse it, according to a study published November 18 in the Journal of Aging. This could potentially one day help prevent age-related illnesses like cancer, diabetes, and dementia. 

The study found that a special oxygen treatment appeared to improve two key markers of biological aging. Following the therapy, participants had a significant increase in the length of their telomeres, a compound in chromosomes that stabilizes our DNA as cells divide.

As we age, telomeres shorten — a phenomenon linked to greater risk of age-related illnesses such as cancer and type 2 diabetes. 

Researchers also noticed a significant decrease in senescent cells, which have been linked to age-related diseases.

These findings are a potential breakthrough for anti-aging research, according to Dr. Shai Efrati, lead researcher on the study who pioneered research on this type of therapy at Tel Aviv University. 

"For the first time in humans, we can see that we're not only slowing decline, but the opposite — we can reverse it," Efrati told Insider. "We see an elongation [of telomeres] of more than 20%, something that was considered impossible in humans." 

The experimental therapy is promising, but expensive and time-consuming. More research is needed to see how lengthening telomeres might affect chronic illnesses and longevity and what side effects might occur long-term.

The therapy floods the body with oxygen, similar to what astronauts and deep-sea divers undergo

In the study, researchers from Shamir Medical Center and Tel Aviv University treated 30 healthy adults over age 65 with a type of hyperbaric oxygen therapy. Five days a week for three months, participants spent 90 minutes inside a compression chamber, breathing 100% oxygen from a mask, with five-minute breaks at regular intervals to breathe normal air. 

Hyperbaric oxygen therapy has previously been used as treatment for a wide variety of conditions, including carbon monoxide poisoning and decompression sickness. For this reason, it's useful for scuba divers and astronauts who face hostile environmental conditions such as extreme pressure in the deep ocean or outer space. 

But the therapy used in this study is different from what you might find in clinics . Every 20 minutes, participants remove the oxygen mask, prompting a quick decline to normal oxygen levels. The body interprets this abrupt change as a sudden lack of oxygen, which creates a chain reaction. 

"There is a biological cascade that initiates the generation of new tissue, and more importantly, we see that on the cellular level, activating telomeres," Efrati said. 

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Years of research made this latest innovation possible

Efrati's original "a-ha moment" was the publication of a NASA study on twins. The study found the twin that went to space came back with longer telomeres, while the twin who stayed on Earth experienced normal shortening of telomeres over time. 

"When I saw that, I opened a bottle of champagne. Everyone looked at me as crazy," Efrati said. "But it means when we are changing the environmental conditions, it can change the basic biology and increase telomere length, which is considered to be the holy grail of aging."

Efrati's previous work on hyperbaric oxygen therapy has tested whether it can help treat cognitive issues and traumatic brain injury. Other researchers have been skeptical of his claims, the Washington Post reported, noting a lack of data on these experimental uses of the therapy. 

Similarly, the claims of his latest study, that aging can be reversed, almost seem too good to be true. 

"If it was magic, we wouldn't have needed 20 years to get where we are now. I hope my next research happens by magic so it happens immediately," he said. "This isn't magic, it's hard work."

The long-term effects are unknown

It's not yet clear how lengthening telomeres might affect aging, chronic illness, and longer lifespan, since it's never been done before. 

But the research does show we can measure, and possibly control, this important marker of aging.

"Once we can measure telomeres, once we can see the elongation, hopefully it will be just like blood pressure. You can measure it, you can treat it," Efrati said.

With more research, the goal is to treat aging as a preventable disease, and stave off related illnesses, such as cancer, diabetes, and cognitive decline. Efrati hopes to study the treatment in a larger population that includes people who are at risk of or in early stages of these diseases.  

"We need to see the long term effects, and to see if we can tailor the treatment for individuals to optimize the protocol," he said. 

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Lifestyle factors still play a key role in aging 

While the therapy is promising, even these early results suggest that it's not a magic solution to all age-related health issues. 

Factors like diet, exercise, and lifestyle still play an important role in how we age.  Eating a healthy diet, and exercising regularly, for example, have both been shown to stave off cellular degeneration, while unhealthy habits like eating poorly, being sedentary, and smoking appear to speed aging. 

As a result, Efrati said someone could theoretically receive the treatment, but continue to see their health deteriorate if those negative factors outweigh the positive. 

The procedure is expensive and time-consuming 

It's not likely that Efrati's treatment will be available to the public anytime soon, since it requires extremely specialized equipment, lots of resources, and a big time commitment.

"Every time we are starting something new, it starts with a small group of people who can afford it," Efrati said. "The type of treatment that we are giving is not affordable and available for all."

Other labs are already working to replicate his therapy, advancing our understanding of its potential and bringing it a step closer to widespread use. But, he said, it's not a process that can be rushed.

"We are dealing with human biology and human health. It's very important we do it in an appropriate way, with the quality that's needed and without any shortcuts," Efrati said.  

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Yes, it’s safe to go to the dentist

  • There has been no evidence of coronavirus transmission in dental offices since many reopened in May.
  • Dentists have universal precautions in place to prevent the transmission of any infectious disease.
  • Oral health has a cascading effect on overall health, so it’s important to keep up with your cleanings and preventive dental care.
  • Visit Insider's homepage for more stories.

Some people might be hesitant to visit the dentist during the coronavirus pandemic, especially after the World Health Organization suggested not to in an August announcement.

However, it's actually a low-risk activity for the patient, said Amesh Adalja, an infectious disease expert at the Johns Hopkins University Center for Health Security. 

"I would be more worried about my dentist than I would myself contracting the virus there," Adalja told Insider.

Dentists aren't too concerned either. After the WHO's recommendation to delay routine dental care in certain situations due to COVID-19, the American Dental Association released a statement saying it "respectfully yet strongly disagrees."

"Our first job is to be sure that our patients are safe," American Dental Association President Chad Gehani, DDS, told Insider. "If we did not think that the patients were safe, we simply would not go to the office at all. We would not have even done the emergency care in the months of March, April, and May."

Since mid-May, most dental offices in the US have been open for routine care. During those four months, there has been no evidence of COVID-19 transmission in dental offices, Kami Hoss, DDS, said — "a remarkable track record."

Along with implementing new screening procedures, dentists have taken steps to clear out their waiting rooms, reduce the potential aerosols created by some dental procedures, and ramp up personal protective equipment worn by dental professionals since reopening.

Dentists treat every patient like they could have every infectious disease

Dentists have been dealing with the possibility of coming into contact with infectious diseases from HIV to hepatitis since well before the coronavirus pandemic.

"As a profession, we are infection control experts," Hoss said. "We've always had to deal with infectious diseases and diseases that are easily transmitted via air or through blood." 

It's already standard practice for dentists and hygienists to wear masks and gloves to decrease their risk of transmitting or contracting diseases, and they've only stepped up their PPE since the pandemic, Hoss said.

The ADA also recommends additional precautions to reduce the creation of aerosols, which can carry viral particles through the air. Those measures include using high-powered suction whenever possible, and, for longer procedures, limiting exposure with rubber dental dams.

You won't find magazines in waiting rooms anytime soon

Back when dental offices in the US closed to non-emergency care in March, the primary concern was transmission in crowded waiting rooms, not during dentist-patient interactions, Gehani said.

The ADA has since encouraged dentists to limit the amount of people that pass through their offices and take away some of the shared objects they might touch. At Gehani's practice in New York, a waiting room that could hold 14 people now seats four — and there are no magazines in sight.

Hoss said the check-in process that used to take place in his waiting room is now almost entirely virtual. Patients undergo a phone screening before they book an appointment, fill out forms online instead of at reception, and they're screened again and get their temperature checked before they enter the office.

Oral health affects your overall health, so now is not the time to skip your cleaning

Much of dental care is preventive in nature, Hoss said, so it's important to keep up with regular cleanings and not put off filling cavities. Delaying a simple procedure could result in a much more costly, involved operation down the line.

Poor oral hygiene can also have "cascading effects" on other aspects of your health, Adalja said. He said he never advocated for the closure of dental offices during the pandemic because he considers dentistry to be an essential health service.

Studies have shown gum disease is associated with a higher risk of dementia, heart disease, and rheumatoid arthritis, among other health issues. And according to a pre-print of a study due to be published in the Journal of the California Dental Association next month, COVID-19 patients with gum disease have a higher risk of developing acute respiratory complications and dying.

"During a pandemic, one of the best things we can do is to stay healthy, and staying healthy starts with our oral health," Hoss said.

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Moisturizer can be the most important part of your skincare routine. Here’s how to do it right.

  • Moisturizer is one of the most important parts of skincare, as it prevents premature aging and can help with acne.   
  • But sometimes it can be hard to know when to put it on.
  • Here is how to properly apply moisturizer and why it's one of the most important parts of any skincare regimen, according to dermatologists. 
  • Visit Insider's homepage for more stories.

Moisturizing is one of the most important parts of any skincare routine but it can be hard to figure out what kind to look for, and how to reap the benefits from it. 

Here is a step-by-step, dermatologist-approved guide on exactly how and when to apply moisturizer, why moisturizer is important, and what to look for when you're buying one. 

Why is moisturizer so important?

Hydration is crucial for your skin's ability to regulate itself. While the overproduction of oil can cause breakouts, so can dryness.

Moisturizing your face can reduce your chance of developing extreme dryness or oiliness, according to the University of Tennessee Medical Center. 

While it's a common misconception that people with acne shouldn't add more moisture to the equation, moisturizing your skin twice a day in the mornings and night after cleansing can actually reduce the overproduction of oil in your skin and decrease your acne.

According to cosmetic dermatologist, Dr. Heidi Waldorf, well-moisturized skin will be more likely to control oiliness on its own. 

"[Healthy skin] holds in moisture and exfoliates on its own, is soft to the touch, and reflects light well," Waldorf said. 

Using a moisturizer can also prevent premature aging like wrinkles and fine lines. 

What should you look for when you're buying moisturizer?

Effective moisturizers use humectants to pull in moisture, emollients to smooth the surface and provide a silky feel, and an occlusive to lock the moisture in.

If you have oily skin, try looking for a moisturizer in a gel consistency as it can feel less heavy on your skin but still do the trick. in terms of hydration. 

For normal to dry skin, a cream moisturizer can help balance your skin all day rather than leaving it thirsty midway through. 

How do I apply it?

While it may depend on your specific skin needs, generally you should apply moisturizer in the morning and before you go to bed.

According to Waldorf, the best time to apply moisturizer is after your other skincare steps, but before sunscreen. If you have steps beyond cleansing — like toner, applying serums, and exfoliating — you should apply your moisturizer to seal in all of the beneficial skin treatments. 

If you prefer to just cleanse and moisturize, make sure to leave your face a little bit damp before applying your moisturizer on top. This will seal in the additional moisture from the water. 

In the morning, you should layer your moisturizer under your sunscreen to protect your skin from the sun's harsh UV rays, which can also cause damage. 

If you feel like you want extra moisture at night, you can double up and put on a night cream, which oftentimes is a heavier duty moisturizer that is thicker than your daytime one. 

Read More:

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The best facial cleanser ingredients for each skin type, according to dermatologists

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