Monday, September 25, 2023

Why Do Some Vaccines Last Longer Than Others

If I Have Natural Immunity Do I Still Need A Covid Vaccine

Why do natural immunities after COVID last longer in some than others?

Yes, the COVID-19 vaccines are recommended, even if you had COVID-19. At present, evidence from Johns Hopkins Medicine and the U.S. Centers for Disease Control and Prevention supports getting a COVID-19 vaccine as the best protection against getting COVID-19, whether you have already had the virus or not.

Here are recent research studies that support getting vaccinated even if you have already had COVID-19:

Vaccines add protection.

  • The U.S. Centers for Disease Control and Prevention released a report on Oct. 29, 2021, that says getting vaccinated for the coronavirus when youve already had COVID-19 significantly enhances your immune protection and further reduces your risk of reinfection.
  • A study published in August 2021 indicates that if you had COVID-19 before and are not vaccinated, your risk of getting re-infected is more than two times higher than for those who got vaccinated after having COVID-19.
  • Another study published on Nov. 5, 2021, by the U.S. Centers for Disease Control and Prevention looked at adults hospitalized for COVID-like sickness between January and September 2021. This study found that the chances of these adults testing positive for COVID-19 were 5.49 times higher in unvaccinated people who had COVID-19 in the past than they were for those who had been vaccinated for COVID and had not had an infection before.
  • A study from the CDC in September 2021 showed that roughly one-third of those with COVID-19 cases in the study had no apparent natural immunity.

When Were Vaccines Developed

Vaccines are not new immunisation techniques were pioneered over 200 years ago, when smallpox was a feared and deadly disease. An eighteenth-century doctor named Edward Jenner noted that workers on farms who contracted the mild cowpox disease were immune to smallpox. Jenner guessed that the germ responsible for cowpox was similar enough to the smallpox germ to train the immune system to defeat both diseases. He was correct. Immunisation in Australia today relies on similar principles.

How Do Vaccines Help Our Immunity

Our immune system is like a library it stores information about every germ ever defeated. We sometimes call this immunological memory.Some antibodies remain on patrol in our bloodstream. So if we ever encounter the real germ in the future, our immune system can quickly trigger the memory cells and produce antibodies to defeat it. And this often occurs before we experience any symptoms of illness. Each vaccine is designed according to how the specific germs make us sick. For example, measles is the result of the bodys reaction to the whole virus and so the vaccine contains a weakened form of the virus. On the other hand, tetanus is caused by the bodys reaction to the toxin produced by the tetanus bacteria and so the vaccine contains inactivated tetanus toxin.

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How Do Vaccines Work

Our immune system is made up of special cells and chemicals that fight infection. We gain immunity against diseases either naturally , or through immunisation.Vaccines are made up of a modified version of a disease-causing germ or toxin , alternatively mRNA vaccines instruct our cells to stimulate an immune response. They are usually given by injection or a small drink that contains the vaccine. The immune system responds to the weakened, partial or dead germ or inactivated toxin as if it was a fully-fledged germ, and makes antibodies to destroy it. These antibodies are made without us catching the illness.

How Does Omicron Mimic A Vaccine

More than 10 million people receive first dose of COVID

All vaccines work on the principle of training the immune system to fight against an infectious agent. Each vaccine, regardless of how it is made, exposes the human or animal host to the critical molecules used by the infectious agent in this case, the SARS-CoV-2 virus to gain entry into the hosts cells.

Some vaccines expose the host only to select portions of the virus. For example, the Pfizer-BioNTech and Moderna vaccines use a molecule called messenger RNA, or mRNA, to encode and produce a fragment of the spike protein the knobby protrusion that is expressed on the outside of SARS-CoV-2 viruses inside a persons body. These spike proteins are the key way that the coronavirus invades cells, so the mRNA vaccines are designed to mimic that protein and trigger an immune response against it.

In contrast, some vaccines against other infections, such as chickenpox and measles, mumps and rubella , expose the host to a live attenuated form of the virus. These vaccines use small amounts of a weakened form of the live virus. They mimic a natural infection, trigger a strong immune response and afford lasting resistance to infection.

In some respects, omicron mimics these live attenuated vaccines because it causes milder infection and trains the body to trigger a strong immune response against the delta variant, as shown in a recent study that is not yet peer-reviewed from South Africa.

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What Is In Vaccines

Depending on the infection, ingredients in vaccines can vary. They may also change from year to year as new strains of viruses appear. Some vaccines may contain a small dose of:

  • A live germ.
  • Dead germs.
  • Small parts of germs .
  • Inactivated toxins produced by bacteria.
  • Antibiotics or preservatives to stop the vaccine from becoming contaminated or going off.
  • Diluents .

Alternatively mRNA vaccines teach our cells how to make a protein that stimulates an immune response.

Australia has strict rules on vaccine safety. Before a vaccine is registered by the Therapeutic Goods Administration and made available to the public it goes through rigorous testing. And, even when it is used, it is constantly monitored for safety and effectiveness.

Vaccine Safety: Immune System And Health

Some concerns about vaccine safety relate to how vaccines interact with the immune system or even how the immune system functions in different situations . While it is fair to consider these concerns, it is important to understand them in the context of how the immune system works.

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What Is Natural Immunity

Natural immunity is the antibody protection your body creates against a germ once youve been infected with it. Natural immunity varies according to the person and the germ. For example, people who have had the measles are not likely to get it again, but this is not the case for every disease. A mild case of an illness may not result in strong natural immunity. New studies show that natural immunity to the coronavirus weakens over time, and does so faster than immunity provided by COVID-19 vaccination.

Johns Hopkins Research On Natural Immunity For Covid

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Johns Hopkins has conducted a large study on natural immunity that shows antibody levels against COVID-19 coronavirus stay higher for a longer time in people who were infected by the virus and then were fully vaccinated with mRNA COVID-19 vaccines compared with those who only got immunized.

The data show that one month after they got their second shot, participants who had had COVID-19 more than 90 days before their first shot had adjusted antibody levels higher than those who had been exposed to the coronavirus more recently than 90 days. Three months after the second coronavirus vaccine, the antibody levels were even higher: 13% higher than those who were exposed to the virus less than or equal to the 90-day mark.

These study results suggest that natural immunity may increase the protection of the shots when there is a longer time period between having COVID-19 and getting vaccinated.

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Why Some Vaccines Require More Than One Dose

Despite being declared beaten in 2000, measles is back, due largely to declining vaccination rates in parts of the United States.

“We should not be in this boat,” Dr. Pritish Tosh, an infectious diseases physician and researcher at the Mayo Clinic, told The Huffington Post. “This is a completely preventable disease.”

That’s because of the measles, mumps and rubella vaccine, which Tosh called “phenomenal” in its ability to protect large percentages of the general population.

The vaccine is one of several different vaccines, however, that are given in multiple doses. Children receive the first dose of the MMR vaccine between 12 and 15 months and the second before they go to school, around age 4 to 6.

Every vaccine ever created has to take many variables into consideration, he explained, including the individual pathogen or bug how our immune systems respond to it what parts of the bug can be used to generate an immune response that is protective in nature and also how long that response will last. Because that equation is notably complex, sometimes a second dose is a good idea.

“Sometimes, if you take a large group of people with one vaccination you might expect 90 percent ,” he said. “But if you give a second dose, you may get up to 98 percent.” Rather than testing the population to find the 10 percent not protected by the first dose, “what is probably a more straightforward strategy is just giving two doses to insure you have that high level of protection,” he said.

How Are Vaccines Studied And Improved

The FDA’s Center for Biologics Evaluation and Research is the government agency that regulates vaccines in the United States. Working with the CDC and the NIH, they continuously research and monitor vaccine safety and effectiveness.

New vaccines are licensed only after thorough laboratory studies and clinical trials, and safety monitoring continues even after a vaccine has been approved. There have been and will continue to be improvements that will minimize potential side effects and ensure the best possible safety standards.

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Naturally Acquired Immunity Is At The Center Of A Political Fight Over President Bidens Vaccine Mandates


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Its a question that scientists have been trying to answer since the start of the pandemic, one that is central to the rancorous political debates over coronavirus vaccine policies: How much immunity does someone have after recovering from a coronavirus infection, and how does it compare with immunity provided by vaccination?

The Centers for Disease Control and Prevention has weighed in for the first time in a detailed science report released with little fanfare Friday evening. Reviewing scores of research studies and its own unpublished data, the agency found that both infection-induced and vaccine-induced immunity are durable for at least six months but that vaccines are more consistent in their protection and offer a huge boost in antibodies for people previously infected.

In comparing the two types of immunity, scientists said research shows vaccination provides a higher, more robust, and more consistent level of immunity to protect people from COVID-19 than infection alone.

The CDCs bottom line: Given whats known and not known about immunity, people who have been infected with the virus should still get vaccinated. More than 45 million people in the United States have had confirmed coronavirus infections, and tens of millions more the exact number is unknown have had undocumented cases.

Antibodies From Natural Infection

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When you develop antibodies through illness, your immune system reacts to protect you. First, it goes through a process of identifying the virus and eventually making effective antibodies.

Your B cells make antibodies to different parts of the virus. Some of the antibodies your body makes are effective, and some are not. These help you eliminate the virus and recover.

Hopefully, some of these antibodies also help protect you from future infections. For example, infection with COVID-19 seems to give you some protection from being re-infected, at least in the short term. However, it is still unknown how long that protection lasts.

Vaccine data as of August 2021 shows that the odds of being reinfected with COVID-19 are 2.34 times greater for those who are unvaccinated than those who have received COVID-19 vaccination.

Also, studies have indicated that people with symptoms of COVID-19 seem to produce effective, neutralizing antibodies. From experience with other viruses, scientists think it means that getting infected with COVID-19 probably leads to at least some level of protection against future infection.

Additionally, animal studies suggest at least some level of protective immunity, with at least some of this coming from antibody protection.

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The Immune Systemthe Bodys Defense Against Infection

To understand how vaccines work, it helps to first look at how the body fights illness. When germs, such as bacteria or viruses, invade the body, they attack and multiply. This invasion, called an infection, is what causes illness. The immune system uses several tools to fight infection. Blood contains red blood cells, for carrying oxygen to tissues and organs, and white or immune cells, for fighting infection. These white cells consist primarily of macrophages, B-lymphocytes and T-lymphocytes:

Vaccines prevent diseases that can be dangerous, or even deadly. Vaccines greatly reduce the risk of infection by working with the bodys natural defenses to safely develop immunity to disease. This fact sheet explains how the body fights infection and how vaccines work to protect people by producing immunity.

  • Macrophagesmedia icon are white blood cells that swallow up and digest germs, plus dead or dying cells. The macrophages leave behind parts of the invading germs called antigens. The body identifies antigens as dangerous and stimulates antibodies to attack them.
  • B-lymphocytes are defensive white blood cells. They produce antibodies that attack the antigens left behind by the macrophages.
  • T-lymphocytes are another type of defensive white blood cell. They attack cells in the body that have already been infected.

Why Do Some Vaccines Last A Lifetime

Memorial HermannOctober 18, 2021

Ever since the U.S. Food and Drug Administration granted Emergency Use Authorization to the first COVID-19 vaccine last December, the research, development and science behind vaccines has become a household topic like never before. But vaccines themselves date as far back as the late 1700s when a physician from Gloucestershire, England created an experimental therapy during a smallpox outbreak in an attempt to save a little boys life. As the story goes, Dr. Edward Jenner took fluid from cowpox lesions and scratched a small amount into the eight-year-olds skin the boy became mildly ill but then recovered and survived the deadly outbreak.

It was one of the earliest experiments to use exposure to a virus as a way of harnessing the immune system to create antibodies. Since then, scientists have developed vaccines for some of the worlds most contagious and dangerous diseasesincluding one that, thanks to widespread distribution, lead to the eradication of smallpox across the globe.

But why do vaccines vary so much in type, dosage, and administration schedules? For example, why do we get a vaccine against seasonal influenza each year, a vaccine against tetanus every 10 years, and yet the measles vaccine we receive as children lasts a lifetime?

Yancey said that for vaccines that last a lifetime, which include vaccines for measles or hepatitis B, the viruses themselves tend to be uniform when they replicate.

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How Do Vaccine Boosters Work

A vaccine contains weakened forms of the disease-causing virus or bacteria, or parts of these germs. Or it may be made of an altered genetic “blueprint” for the germ that can make you sick.

The shot triggers your immune system to attack the foreign organism, like it would if you actually got the disease.

This helps your immune system “remember” the disease-causing germ. If youâre exposed to it again, the antibodies can recognize and kill it before it causes harm.

Research has shown that booster shots train your body to recognize the virus or bacteria and defend itself. Depending on the type of vaccine and the manufacturer, you might get a booster weeks, months, or even years after your first shot.

Natural Immunity Alone Is Weak

Why are some vaccines more effective than others?

One study compared natural immunity alone to natural immunity plus vaccination. They found that, after infection, unvaccinated people are 2.34 times likelier to get COVID-19 again, compared to fully vaccinated people. So vaccinated people have half the risk of reinfection than people relying on natural immunity alone.

“Studies show that the vaccine gives a very good booster response if you’ve had COVID-19 before,” says Dr. Rupp.

Furthermore, there is no country on the globe in which natural infection and natural immunity has brought the pandemic under control. In countries like Iran or Brazil very high levels of natural infection have not prevented recurrent waves of infection.

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Should I Hold Off Getting A Covid Vaccine To See If There Is New Research On Natural Immunity

Holding off on getting vaccinated for COVID-19 is not a good idea. Heres why:

  • Getting COVID-19 is very riskyand can result in long-term disease, lasting organ damage, hospitalization or even death.
  • Even if your own infection is mild, you can spread it to others who may have severe illness and death.
  • The authorized and approved vaccines are safe and highly effective against severe illness or death due to COVID.
  • Risks of COVID-19 vaccine side effects are extremely low.
  • For the reasons above, the CDC recommends and Johns Hopkins Medicine agrees that all eligible people get vaccinated with any of the three FDA-approved or authorized COVID-19 vaccines, including those who have already had COVID-19.

    Who Needs Booster Shots

    You may get booster shots as a baby, teen, or adult. You may also need to re-up some vaccinations depending on your lifestyle, travel, or job .

    Vaccine boosters that children need include:

    • Varicella
    • MMR

    Experts recommend that both children and adults get the seasonal flu shot each year. While itâs not 100% effective, it may prevent severe illness. Flu shots are especially important for pregnant women, older adults, and those who have chronic conditions like diabetes or high blood pressure.

    During each pregnancy, women need the Tdap vaccine to protect against whooping cough. You usually get it between weeks 27 and 36 of your pregnancy. Along with the flu and Tdap vaccine, health care workers should stay up to date on their hepatitis B, MMR, chickenpox, and meningitis shots.

    International travelers may need certain vaccines, depending on their destinations. Antibodies from these vaccines wear off over time, so make sure you’re up to date on vaccines for diseases like typhoid. The CDC’s Traveler’s Health page can help you find out which ones you need.

    If youâre not sure which disease you need a booster for, ask your doctor.

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