Two Studies Show Covid
Posted on by Dr. Francis Collins
More than 8 million people in the United States have now tested positive for COVID-19. For those whove recovered, many wonder if fending off SARS-CoV-2the coronavirus that causes COVID-19one time means their immune systems will protect them from reinfection. And, if so, how long will this acquired immunity last?
The early data brought hope that acquired immunity was possible. But some subsequent studies have suggested that immune protection might be short-lived. Though more research is needed, the results of two recent studies, published in the journal Science Immunology, support the early data and provide greater insight into the nature of the human immune response to this coronavirus .
The new findings show that people who survive a COVID-19 infection continue to produce protective antibodies against key parts of the virus for at least three to four months after developing their first symptoms. In contrast, some other antibody types decline more quickly. The findings offer hope that people infected with the virus will have some lasting antibody protection against re-infection, though for how long still remains to be determined.
They found that all three types were present by about 12 days after infection. IgA and IgM antibodies were short-lived against the spike protein that crowns SARS-CoV-2, vanishing within about two months.
What reinfections mean for COVID-19. Iwasaki A. Lancet Infect Dis, 2020 October 12.
How Long Does Immunity Last After Covid
- For people who recover from COVID-19, immunity to the coronavirus can last about 3 months to 5 years, research shows.
- Immunity can occur naturally after developing COVID-19 or from getting the COVID-19 vaccination.
- Because the length of immunity after developing COVID-19 or getting the vaccine is unknown, practicing physical distancing and wearing a mask need to continue to stop the spread.
Whether youve recovered from COVID-19, received the vaccine, or neither, understanding immunity and how long it lasts can help give you important insight into how you can interact safely with others during the pandemic.
First, it helps to know what immunity means.
There are two types of immunity: natural and vaccine-induced.
After a person acquires a virus, the immune system retains a memory of it.
The explains, Immune cells and proteins that circulate in the body can recognize and kill the pathogen if its encountered again, protecting against disease and reducing illness severity.
The components of immunity protection include:
- Antibodies are proteins that circulate in the blood and recognize foreign substances like viruses and neutralize them.
- Helper T cells help to recognize pathogens.
- Killer T cells kill pathogens.
- B cells make new antibodies when the body needs them.
People who recover from COVID-19 have been found to have all four of these components. However, specifics about what this means for the immune response and how long immunity lasts are not clear.
How Long Do Covid
The new study found that 98.8% of people infected with coronavirus in February and March 2020 had detectable levels of antibodies in November, according to Imperial College London.
The study which was published in Nature Communications said there was no difference between people who had suffered symptoms of COVID-19 and those that had been symptom-free.
- To find this, researchers tested more than 85% of 3,000 residents in Italy, who had been infected in February and March 2020. The researchers tested those people again in May 2020 and November 2020.
However, the researchers said the antibody levels were different depending on how the patients were tested, showing some people might not have the same level of antibodies as others.
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Is Natural Immunity Safer Than Covid Vaccines
Some people may feel that it is safer to develop immunity to COVID-19 by catching the virus, rather than being vaccinated, due to the reported side effects from the vaccine. However, while many unvaccinated people who catch coronavirus are only mildly sick or have no symptoms at all , some people can fall seriously ill.
Older people and those with underlying health conditions are more at risk of ending up in hospital with COVID-19, but even healthy younger people can become seriously ill or die from the disease. A recent study from the US showed that unvaccinated people are 11 times more likely to die of COVID-19 than those who have been vaccinated.
We also know that up to one in 20 people with COVID-19 end up having symptoms for 12 weeks or more , which can have a big impact on health and quality of life. And unvaccinated people can spread the virus to others, putting them at risk too.
After-effects like having a sore arm or cold-like symptoms are common after having a COVID-19 jab. However, more serious or life-threatening side effects such as allergic reactions, blood clots or heart inflammation are extremely rare, as are deaths due to the vaccine .
âWe can definitely say that the safest way to become immune to COVID is to be vaccinated rather than catching the virus,â says Mike.
âThe data overwhelmingly shows that you are at far greater risk of being seriously ill, suffering long-term symptoms or dying compared with any rare side effects from vaccination.â
If You’ve Had Covid This Is How Long You Have Immunity New Study Finds
There’s not much of a bright side to contracting COVID, but people have at least clung to the hope that they’d acquire some immunity after recovering from the virus. Studies have shown that people who had COVID have maintained some level of antibody response after the infection leaves their system, though it’s still not clear exactly how long those antibodies lastand how thoroughly they protect you from getting sick again. Now, a new study suggests that you may be in the clear for longer than we previously thought. According to recent research, the overwhelming majority of people who have COVID retain antibodies against the virus for at least 10 months.
The study from Labcorp, which was published on May 24 in the medical journal The Lancet, examined samples from more than 39,000 people who were previously infected with COVID. The researchers found that nearly 87 percent of them had antibodies at least 10 months after their infection. The researchers also found that people over 65 generally didn’t hang on to antibodies as long as those under 65.
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Will The Booster Protect You From The Omicron Variant
Research shows that the booster jab does offer more protection. All of the vaccines in our study do show a statistically significant boost, said Professor Saul Faust, trial lead and director of the NIHR Clinical Research Facility at University Hospital Southampton NHS Foundation Trust.
The latest CovBoost trial, published in the Lancet, involved 2,878 people aged 30 or over who received a booster 10 to 12 weeks after their initial two jabs.
Although the newly emerged Omicron variant was not tested in the study, the study showed that booster vaccines are working well against existing variants.
The data clearly shows that all boosters provided a lift to at least one aspect of your Covid immunity, and that side effects were, on the whole, mild, Jonathan Ball, professor of molecular virology at the University of Nottingham, added.
Professor Chris Whitty, Chief medical officer for England, has also previously urged people to be boosted for better protection against Omicron.
Boosters give you the best possible protection against the virus and should significantly reduce your risk of serious illness and hospitalisation, he said. Get your Covid-19 booster vaccine to strengthen your protection. Please, get boosted now.
Who Gets Antibodies After A Covid Infection
Looking more closely at the data, we saw that people who had a greater number of symptoms while they were ill with COVID – particularly the âclassic threeâ symptoms of cough, fever and loss of smell – were more likely to have gained antibodies against the virus.
In contrast, people with one or more health issues associated with an underlying condition were less likely to have antibodies after being infected, as well as people who currently smoke. However, our research can not link smoking directly to reduce immune response and it might be that there are other negative health behaviours involved here that impact the immune system.
There was no link between age, sex/gender or social deprivation with the likelihood of having antibodies afterwards.
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Science Is On Our Side We’ll Help You Make Sense Of It
Because COVID-19 vaccines were just developed this year, messaging earlier in the pandemic was unclear on how long the immunity earned from a vaccine would last. Leading health officials at the Centers for Disease Control and Prevention have since clarified that booster vaccines are necessary to replenish your body’s protection against COVID-19 infection as immunity wanes over time and since we’re still in the thick of the global pandemic, expanding eligibility to all Americans for a booster dose ensures most will keep an optimal amount of antibodies during the winter season into the new year.
How long exactly does it take for a booster dose to impact our immune system? If you’ve already been vaccinated, especially with a two-dose mRNA vaccine series made in part by teams at Pfizer or Moderna, you may recall hearing that you weren’t “fully” vaccinated until two weeks out from your last shot.
The logic and subsequent timeline may not be exactly the same for those who are receiving additional doses this month, which is good news for those who are seeking protection against viral variants, including Omicron.
Data suggests that the immune response to an additional COVID-19 vaccine dose is different than when your body is first introduced to the vaccine and experts are breaking down what that means for you below.
How Long Should You Quarantine Or Isolate
First things first, those who believe they have been in contact with someone who has COVID and are unvaccinated should quarantine. Those who test positive, regardless of vaccination status, must isolate, according to the Centers for Disease Control and Prevention.
Massachusetts General Hospital’s Dr. Ali Raja said he talks to his patients all the time about the difference between isolation and quarantine.
“Quarantine sounds a lot scarier,” he said. “It’s actually when you have been exposed and either aren’t fully vaccinated or you’re not vaccinated at all. You stay home even if you don’t have the virus. Isolation is when you’ve actually tested positive regardless of whether you had symptoms.”
“For either one you stay away from people, stay home for five days, and ideally test negative before coming out of it,” he added.
Here’s more on the differences between the two:
Those who have been within six feet of someone with COVID for a cumulative total of at least 15 minutes over a 24-hour period should quarantine for five days if unvaccinated, or if they are more than six months out from their second vaccine dose, according to updated CDC guidance issued Monday.
Once that period ends, they should partake in strict mask use for an additional five days.
Previously, the CDC said people who were not fully vaccinated and who came in close contact with an infected person should stay home for at least 10 days.
So how do you calculate your isolation period?
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How Are People Tested For Covid
Two kinds of tests are currently available for COVID-19: tests for viral infection and antibody tests.
- A test for viral infection detects the virus or a component of the virus and tells you if you have a current COVID-19 infection. This is done using a swab from your nose or throat, or a saliva sample.
- An antibody test tells if you have antibodies to the SARS-CoV-2 virus. These antibodies may have developed in response to a previous infection by the SARS-CoV-2 virus or in response to vaccination. This test is done using a sample of your blood.
Serology tests aren’t used to diagnose a current SARS-CoV-2 viral infection, since they don’t detect the virus itself.
A positive antibody test means that you have antibodies to the virus that causes COVID-19. The test cannot tell how long ago you may have been infected or determine if you’re protected from reinfection as a result of previous infection.
Does Testing Positive For Covid
Unfortunately, no. Experts dont know whether a positive COVID-19 antibody test means that a person is or will become immune to the COVID-19 virus. As mentioned above, some people dont become immune after being sick. These people may still make antibodies while theyre sick. But their immune systems dont remember how to fight the infection after they get better.
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How Long Do Covid Antibodies Last
Weâve previously found that vaccine-induced protection from COVID starts to fade after a number of months.
In this new research we found that people still had anti-N antibodies at least 9 months after infection, suggesting that protection through natural infection might be longer lasting than vaccine-induced immunity.
However, weâve also discovered that protection through natural immunity is less effective overall than vaccination, so we would always recommend you get vaccinated as soon as youâre eligible.
Our data shows that two doses of the AstraZeneca vaccine give 71% protection against infection, while two doses of the Pfizer vaccine provide 87% protection. But an unvaccinated person with a previous COVID infection has only 65% protection against catching it again.
However, being vaccinated on top of having had COVID provides even better protection – two doses of the AstraZeneca vaccine plus a previous COVID infection give 90% protection, while having COVID plus two Pfizer doses provide 95% protection.
Timing Matters With Testing
Antibody tests for COVID-19 arent perfect. One meta-analysis of 54 studies conducted by Cochrane found that antibody tests performed a week after COVID-19 patients first developed symptoms only detected 30% of people with the virus. After two weeks, testing detected antibodies in 70% of those patients and, after three weeks, antibodies were detected in more than 90% of those tested.
Timing matters because, if you get tested too early after being infected, you may have a negative antibody test in your blood, and it is a waste of time and money to get tested, a professor of pediatric infectious diseases at Seattle Childrens Hospital and University of Washington, who co-authored the recent recommendations on antibody testing, tells Verywell.
The actual test you use doesnt matter, Englund says, adding, getting tested too early may not be helpful.
As for the perfect timing to get a test, its up for debate, Jamie Alan, PhD, an assistant professor of pharmacology and toxicology at Michigan State University, tells Verywell. We can take our best guess at timing but, until we know more, we are still at the best educated guess stage, she says.
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Does Vaccination Make A Difference To Those Who Have Already Had Covid
There is some evidence that vaccination can sharpen immunity in people who have previously been infected with SARS-CoV-2 and recovered. A letter published in the Lancet in March discussed an experiment in which 51 healthcare workers in London were given a single dose of the Pfizer vaccine. Half of the healthcare workers had previously recovered from covid-19 and it was they who experienced the greatest boost in antibodiesmore than 140-fold from peak pre-vaccine levelsagainst the viruss spike protein.14
How Long Does Protection Last After Covid
After your bodys disease defense system fights off a virus, it keeps a memory of it. A study suggests that peoples immune systems remember COVID-19 for months after recovery.
The immune system makes different types of cells and molecules to fight disease. These include antibodies, T cells, and B cells.
Researchers looked at immune responses from about 200 people whod recovered from COVID-19. Some had been infected up to eight months before the analysis. Other cases were more recent. Of the people who recovered, 95% had immune system memories of the virus that causes COVID-19, SARS-CoV-2.
Almost everyone had antibodies that block the virus spike protein. The virus uses this protein to enter cells. The number and type of antibodies varied between people. But the levels usually remained stable over time. They slightly decreased six to eight months after infection.
Immune cell levels also remained high. Memory B cells, which make antibodies, increased for a few months after infection and then remained stable. Most people had one important type of T cell. About half had another type of T cell that kills infected cells.
Several months ago, our studies showed that natural infection induced a strong response, and this study now shows that the responses last, says Dr. Daniela Weiskopf at the La Jolla Institute for Immunology. We are hopeful that a similar pattern of responses lasting over time will also emerge for the vaccine-induced responses.
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How Does Vaccination Protect Against Covid
Vaccines work by training your immune system to recognise and respond to infection, without having to actually catch the disease.
The various vaccines against COVID-19 all work by delivering a small inert/harmless part of the virus into your body – usually the spike protein that makes up the viral coat – in a way that is designed to trigger a strong immune response. This is the same kind of immune response that you would get with a natural infection, but produced in a much safer and more reliable way.
Most of the COVID vaccines that are currently in use are given in two doses, known as a âprime and boostâ approach.
âThe first dose primes your immune system to recognise the virus and start building an immune response, while the second dose amplifies this response and helps lay down a strong immune memory to protect you in the future,â Mike explains
The ZOE COVID Study and many other research studies show that having two or more doses of a COVID-19 vaccine cuts the chances of catching COVID-19 and reduces the risk of being seriously ill or hospitalised if you do get it. Weâve also found that being vaccinated halves the risk of developing long COVID.
Immunocompromised people whose immune systems donât work optimally or are taking immune-suppressing drugs may have a weakened response to the vaccine. These people may benefit from a third jab to reinforce the effect of their first two vaccines.