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Updated on September 25, 2022 10:38 am
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Updated on September 25, 2022 10:38 am
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Updated on September 25, 2022 10:38 am

Global Statistics

All countries
Updated on September 25, 2022 10:38 am
All countries
Updated on September 25, 2022 10:38 am
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Updated on September 25, 2022 10:38 am
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How Long Will Immunity To Covid-19 Last

What Experts Know About Immunity After Vaccination And Whether Booster Shots Will Be Necessary

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Clinical trials and real-world conditions have proved that vaccines protect against COVID-19. But the question remains: How long will vaccine immunity last?

Recent studies have shown promising results that suggest immunity may last for longer than originally expected, but time and additional data are needed to determine exactly how long, says Dr. Sharon Chacko, medical director at the Farrell Community Health Center at NewYork-Presbyterians Ambulatory Care Network and medical director of COVID-19 immunizations in the Division of Community and Population Health.

To learn more about this evolving issue, Health Matters spoke with Dr. Chacko, who is also an assistant professor of medicine at Columbia University Vagelos College of Physicians and Surgeons, about vaccine immunity how long it may last, if some vaccines offer longer protection against COVID-19, and whether booster shots may be needed down the road.

Dr. Sharon Chacko

Health Matters: What do we know about how long immunity lasts after vaccination for COVID-19?Dr. Chacko: Initially, we knew immunity lasted at least six months after vaccination, because the first trials had six months of data at that time. However, these studies are ongoing, and we now know that immunity actually lasts longer than we anticipated. At this point, we dont know for sure how long it will last, but we do know that it is even longer than six months, which is exciting.

How Are We Monitoring The Coronavirus Vaccines

Pfizer and Moderna continue to monitor immunity in people who were given their vaccines in the initial clinical trialsboth companies reported strong overall efficacy at the six-month mark.  

One thing researchers are monitoring in vaccine recipients is levels of antibodies, which are proteins produced by the bodys immune system when it detects harmful substances, and that are easily measured from blood samples. Antibodies are a really good marker for protection against infection, so we will be monitoring those levels for as long as we can measure them, says Akiko Iwasaki, PhD, a professor of immunobiology at Yale School of Medicine.

I tell my family, ‘It’s great that youre vaccinated… But even the vaccines dont have 100% guarantees, so… you want to keep weighing the risks,'” says Yale Medicine infectious diseases expert Jaimie Meyer, MD, MS

A report in The New England Journal of Medicine  in April showed that 33 participants who had received the Moderna vaccine during the Phase I trial had a gradual decline in antibody protectionand, based on the slope, Iwasaki says, that is hopeful news. If antibodies are going down very quickly, you would expect that to last for a short time. The slow decline raises hopes that the mRNA vaccines will be protective for at least a year, if not longer, she says.  

This is a reason why the CDC recommends vaccinations for people who have had a COVID-19 infection as well as for those who have not.

How Long Will Covid

Hank Bernstein, MD: I’m Hank Bernstein, and I’m speaking to you today on behalf of the Vaccine Education Center at Children’s Hospital of Philadelphia. The question, How long will COVID-19 vaccine immunity last? With so much illness and so much death, there was a need for COVID vaccines to be developed at unprecedented speed. Since they’ve only been around for less than a year though, we don’t have exact answers about long-term immunity. It’s also true that we don’t know exactly how much antibody is needed for protection, how long the protection lasts, and whether or not a booster shot will be needed.

Thank you.

How Long Will Immunity Last

It is very likely that for COVID-19 vaccine, given that the length of immunity the vaccine generates is limited, we may have to be vaccinated annually, Chunhuei Chi, ScD, MPH, director of the Center for Global Health at Oregon State Universitys College of Public Health and Human Sciences, tells Verywell.

In this regard, the COVID-19 vaccines currently available are not unusual. Most vaccines, Chi says, have their specific duration of immunity that can range from a few months to decades. The flu vaccine, which immunizes against seasonal influenza for several months, represents one end of the spectrum; the measles vaccine, which immunizes against measles for life, represents the other. The magnitude of variation, Chi says, is the result of the unique combination of characteristics of viruses and vaccines.

The hope, Jere McBride, PhD, director of the experimental pathology graduate program at the University of Texas Medical Branch, tells Verywell, is that the Moderna and Pfizer-BioNTech vaccines will confer immunity for two to three years. In reality, however, the duration could be longer or shorter and will only be determined by conducting studies of people who have received the vaccine.

On April 1, 2021, Pfizer announced that an updated analysis of its Phase 3 trial showed that the vaccine was 91% percent effective overall and 100% effective in preventing severe disease for up to six months.

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.


These doctors warn of COVID-19 symptoms from the delta variant

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.

How Long Should I Wait To Get The Vaccine After Having Covid

Ultimately, its best to talk to your doctor, who can provide medical advice based on the treatment following a positive COVID-19 test.

The Centers for Disease Control and Prevention says that individuals who have been treated with monoclonal antibodies or convalescent plasma should wait 90 days after treatment before getting a vaccine.

If you were not treated with monoclonal antibodies or convalescent plasma, infectious disease expert Kristen Englund of the Cleveland Clinic says the time frame that we recommend for being vaccinated after having a COVID-19 infection is as soon as youre out of quarantine.

The CDC also said one recent study showed that unvaccinated people who already had COVID-19 are more than twice as likely than fully vaccinated people to get COVID-19 again.

Related stories about COVID-19:

Will The Common Cold Give Me Immunity To Coronavirus


The jury is still out on the field of “cross-reactivity” but there may be some infections that look similar enough to the virus that causes Covid that people may gain some protection.

Laboratory tests show the T cells some people made to fight Sars or common cold coronaviruses can also react against the new coronavirus.

How common this is and how much protection it gives is still unknown.

Question: Should We Look At Getting Booster Shots What Should Be The Priority

Dr Rahul Pandit: We know people who have taken two doses or are fully vaccinated, in them the immunity stays strong till 6 to 8 months. Currently, I think, people who are immunocompromised or have some or other immunocompromised disease, in them, maybe the antibodies response doesnt last for long, so may be they will need a booster shot in sometime.Another group which we should be looking at is frontline workers healthcare staff, sanitation workers, policemen, warriors, NGOs, to name a few, because they come in direct contact with the virus on a daily basis. But till the time one dose of vaccination is given to the entire population, till then we cannot take the decision of giving the third dose.

Currently, the number one protection for people against the virus is masking, sanitisation, social distancing followed by vaccination. Till everyone is vaccinated, these three things cannot be avoided.

/5difference Between Natural And Vaccine

Immunity against coronavirus can be built up in two ways, one, by specifically being exposed to the virus and getting infected or through the administration of a vaccine, which builds up immune response by mimicking the infection and generating antibodies.

Both types of immunities offer a similar degree of protection. However, while natural immunity is said to last for different times for any individual, vaccine-driven immunity goes over and beyond and offers additional levels of protection. This is also the reason why people who have already fought the virus are advised to get vaccinated.

Now, while vaccines offer a certainly added advantage and are essential to drive up community-wide immunisation, it’s important to remember that the vaccines we have are still experimental in nature, so there’s no one definition of how long vaccine-driven immunity may last.

Having said that, different vaccines do tend to work differently, and hence, may offer different levels of protection and lasting immunity.

How Long Does The Covid

After vaccination, the human body takes some time to recognize the genetic components of the coronavirus and to make antibodies and T-cells. These then begin to block the virus from entering the body’s cells or kill the infected cells. So, it takes at least two weeks or more for the vaccine to become fully effective.

What To Watch For

The evolving understanding of Covid-19 immunity is critical to public health officials and drugmakers as they hash out the future of vaccinations. Pfizer-BioNTech and Moderna have both suggested booster shots could be necessary as soon as September to re-top immunity levels. However, the U.S. leading government agencies have so far held off on concrete recommendations for whenor how oftenthese could be necessary. 

What About T And B Cell Responses

T and B cells have a central role in fighting off infections and, crucially, in establishing long term immunity. Some T and B cells act as memory cells, persisting for years or decades, primed and ready to reignite a broader immune response should their target pathogen arrive in the body again. Its these cells that make truly long term immunity possible.

A study published in February in Science assessed the proliferation of antibodies as well as T and B cells in 188 people who had had covid-19. Although antibody titres fell, memory T and B cells were present up to eight months after infection. Another study in a comparably sized cohort reported similar results in a preprint posted to MedRxiv on 27 April.

Monica Gandhi, an infectious disease doctor and professor of medicine at the University of California San Francisco, says we have evidence that T and B cells can confer lifelong protection against certain diseases similar to covid-19. A well known Nature paper from 2008 found that 32 people born in 1915 or earlier still retained some level of immunity against the 1918 flu strain, 90 years hence. That is really profound, she says.

/5can Vaccines Grant You Lifetime Protection

Immune system has long

While no vaccines at the moment guarantee a complete 100% efficacy rate, it has been observed that some vaccines may be more effective than others. mRNA vaccines, or messenger RNA technology vaccines, for example have been found to offer a much higher degree of protection in comparison to other vaccines.

A recent small-scale study conducted on people who received mRNA vaccines, published in the scientific journal, Nature, found out that some vaccines, such as Pfizerâs and Moderna were the most likely to mount good immune responses that could last years on. While more research is needed to conclude the findings of the same, this is the first study we have which hints at lifetime protection granted by the vaccines.

In addition, the study has also been able to establish that both the mRNA vaccine candidates offered high levels of protection after both doses. For the same, volunteers in the focus group were tested for COVID-19 every week for 13 weeks. The dearth of positive tests and high antibody prevalence over the months proved that both the vaccines provided peak immunity which was long-lasting.

Will Vaccines Protect Us From Coronavirus

A vaccine is a preparation of weakened microbes of a disease that activates adaptive immunity. The vaccine helps our body in developing long-term immunity against infections, which can last for even decades. It achieves this by provoking the body to produce a long-lived B cell and T cell memory.

Usually, the immunity team takes time to respond to the invader microbe that makes us sick. The virus utilizes this time efficiently, keeps replicating and infecting as many tissues as possible. The vaccine is designed to help our body build up this natural immunity before that specific virus infects, hence serves as a time saver. Successful vaccinations produce sterilizing immunity, a form of immunity that completely blocks recurrent infections.

If the recently created COVID-19 vaccine causes sterilizing immunity, then the pandemic immediately ends and restore day-to-day life.

How Long Do Antibodies Against Covid

Data indicate that neutralising antibodies last for several months in patients with covid-19 but gently fall in number over time. One study, published in the journal Immunity, of 5882 people who had recovered from covid-19 infection, found that antibodies were still present in their blood five to seven months after illness. This was true for mild and severe cases, though people with severe disease ended up with more antibodies overall.

All of the vaccines approved so far produce strong antibody responses. The study group for the Moderna vaccine reported in April that participants in an ongoing clinical trial had high levels of antibodies six months after their second dose. A study in the Lancet found that the Oxford-AstraZeneca vaccine induced high antibodies with minimal waning for three months after a single dose.

Neutralising antibodies are expected to decline in number over time, says Timothée Bruel, a researcher at the Pasteur Institute, given what we know about the immune response to other infections. In April, Bruel and colleagues published a paper in Cell Reports Medicine that looked at antibody levels and functions in people who had experienced symptomatic or asymptomatic covid-19. Both types of participant possessed polyfunctional antibodies, which can neutralise the virus or assist in killing infected cells, among other things.

Protection Lasts For At Least 6 Months Likely Longer

Separately, Pfizer-BioNTech said that the ongoing phase 3 clinical trial of its mRNA vaccine shows that strong immunization persists for at least 6 months among vaccinated individuals.

Researchers found that the vaccine was 100 percent effective against severe disease as defined by the CDC, and 95.3 percent effective against severe COVID-19 as defined by the Food and Drug Administration .

The vaccine was also found to be 100 percent effective against one of the main COVID-19 variants currently circulating widely in South Africa.

A study that included 12,000 vaccinated individuals also found no serious safety concerns with the Pfizer-BioNTech vaccine, the companies announced.

The good news is that in the 6-month status report from Pfizer, immunity stays very strong, and we anticipate that it will continue to stay strong, said Bailey.

These people have had the vaccine the longest, and it tells us it lasts at least 6 months, added Bailey. But its definitely longer than that its not just going to drop off after 6 months. I would have been concerned if efficacy had dropped by a third or half.

The fact that COVID-19 vaccine effectiveness remained almost unchanged over the span of the study period is an indication that protection will be enduring.

Bailey noted that some vaccines, such as those for measles, mumps, and rubella, generally confer lifetime immunity. Others, such as the flu vaccine, require a new shot every year.

Does A Covid Infection Make You Immune From Further Infections

An infection creates an immune response and recognizes the coronavirus. Antibodies are also produced.

A previous infection offers about 80% protection from the coronavirus, while those who received both doses of the Moderna and Pfizer vaccines have about 95% protection against the viruses, Dr. John Wherry told WHYY. Wherry is the director of the Institute for Immunology at the Perelman School of Medicine at the University of Pennsylvania.

So while protection is good for those who already caught COVID-19 in some form or another, it is not as strong as the vaccines.

Question: What Are Breakthrough Infections

Dr Rahul Pandit: When we look at the word breakthrough it means that there was something that was stopping the infection from happening, that stopping is caused by the antibodies present in the patients body. Now, where does these antibodies come from, these come when we vaccinate a person. So, once you have completed the schedule of the vaccine and 15 days have gone beyond that then you have essentially got the complete immune status. But still when the person gets infected with COVID-19 infection then that is called a breakthrough infection.

If I Have Antibodies Am I Immune

This is not guaranteed and that is why the World Health Organization is nervous about countries using immunity passports as a way out of lockdown.

The idea is if you pass the antibody test then you are safe to go back to work. This would be particularly valuable for staff in care homes or hospitals who come into contact with those at risk of developing severe symptoms.

But while you will find some antibodies in nearly every patient, not all are equal. Neutralising antibodies are the ones that stick to the coronavirus and are able to stop it infecting other cells. A study of 175 recovered patients in China showed 30% had very low levels of these neutralising antibodies.

That is why the World Health Organization says “that cellular immunity may also be critical for recovery”.

Another issue is that just because you might be protected by your antibodies, it doesn’t mean you cannot still harbour the virus and pass it onto others.

How Long Will The Coronavirus Vaccines Protect You Experts Weigh In


The Washington Post is providing this important information about the coronavirus for free. For more free coverage of the coronavirus pandemic, sign up for our Coronavirus Updates newsletter where all stories are free to read.

You may be among the more than 95 million people in the United States who have taken at least one dose of a coronavirus vaccine. Or you may still be awaiting your turn. Regardless, theres a crucial question on most of our minds: How long will the vaccine really protect us?

As with most aspects of the virus, the answer is not completely clear. Why? Because although we have been battling the pandemic for more than a year, the vaccines were granted emergency use authorization relatively recently. So experts have not had time to observe their long-term effectiveness.

However, that research is underway, and in the meantime, experts say we can make an educated guess.

Is One Dose Enough After Covid

Covid 19 coronavirus:

Some reports have suggested people whove had COVID need only one dose of the vaccine. Clinical trials of approved vaccines didnt generate relevant data because people whod already had COVID were excluded from phase 3 trials.

One study from June showed people with previous exposure to SARS-CoV-2 tended to mount powerful immune responses to a single mRNA shot. They didnt gain much benefit from a second jab.

A single dose of an mRNA vaccine after infection achieves similar levels of antibodies against the spike proteins receptor binding domain compared to double doses of vaccination in people never exposed to SARS-CoV-2.

We need more studies to fully understand how long memory B-cell and T-cell responses will last in both groups.

Also, a single dose strategy has only been studied for mRNA-based vaccines. More data is required to understand whether one jab post-infection would be effective for all the vaccines.

At this stage, its still good to have both doses of a COVID vaccine after recovering from COVID.

Is The Common Cold Grant Us Immunity For Coronavirus


The scientists are still figuring out the cross-reactivity among different types of flu viruses.

Laboratory experiments have shown that the T cells of certain people who suffered from SARS or common cold coronaviruses may even fight the novel Coronavirus.

How much protection it provides is unclear yet.

How Long Until We Could Reach ‘herd Immunity’

As Gauteng premier David Makhura sets a goal to vaccinate 100,000 people a day, many have asked for how long that target will need to be maintained before SA reaches herd immunity.

The government set a target of vaccinating 40 million people, or 67% of the population, to reach a point where enough people are immune to the virus that it stops spreading dangerously.

So far SA has vaccinated 11.6-million citizens, which is 29% of the goal.

The vaccine has, as of last week, been opened to all citizens over the age of 18, and government has introduced several initiatives to get the vaccine to the people.

This includes providing free transport to vaccination sites and pop up vaccination sites in high-traffic locations.

Using statistics from the government’s Covid-19 vaccine data dashboard, SA has on average administered about 165,000 jabs a day over the last week .

According to a vaccine calculator developed by Media Hack., if this trend continues we could reach herd immunity by May next year.

If Makhura’s goal is reached, adding 30,000 to that trend daily, we could reach herd immunity by March 2022.

However, Wits University professor of vaccinology Dr Shabir Madhi warned recently that herd immunity may be far off.

The thinking was that the pandemic would ebb and then mostly fade once a chunk of the population, possibly 60% to 70%, was vaccinated or had resistance through a previous infection.

How Does Immunity Work After The Infection

To understand how Covid immunity works, you must first have some understanding of how viruses work and how your immune system responds to them.

You can think of a virus as a piece of genetic material thatâs surrounded by a protein coating. These viruses are unable to reproduce unless they can find a host cell, which is why they seek out cells in the human body.

Once a virus enters your body, it will locate a cell to inject with its genetic material. It can then take over the control of that cell and begin multiplying.

To combat this process, your bodyâs immune system must work to destroy these infected cells. When your body first encounters a new viral infection, such as Covid-19, it will deploy T cells. Their job is to find and kill any cells that are infected with the virus. 

If the T cells are unsuccessful, the virus will continue to reproduce. Your body will then deploy B cells, which have antibodies that are better equipped to battle the infected cells.

After youâve overcome the infection, antibodies to Covid will remain in your body. Theyâre there to help fight off any infection that may occur in the future. The length of time that these antibodies stay in your system will vary. For some illnesses, theyâll only be present for days, but for others, theyâre present for a lifetime.

Question: How Much Protection Do We Get From Covid

Dr Rahul Pandit: There was a study done by Christian Medical College Vellore, it was done on 24,000 healthcare workers, who were double vaccinated. In that study, when breakthrough infections were studied, it was found that a very small percentage of those healthcare workers got infected with COVID-19 again, there was just one mortality that was reported and maximum individuals there did not require any hospitalisation or ICU or oxygen support, proving that vaccines are very safe and effective. Why do I say so healthcare workers are one who are most prone to catch the virus as they see and deal with the virus on a day to day basis. Now, if the breakthrough infections are happening less in them then it only means that our vaccines are effective.

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