Given the widespread impact of the COVID-19 pandemic, many people are interested in understanding the length of time that antibodies generated from infection will remain effective. This information is important for vaccine development and public health policies.
While there is no clear-cut answer yet, ongoing research has shed some light on the matter.
What are antibodies?
Immune systems create proteins called antibodies, often referred to as immunoglobulins, to help defend the body against harmful pathogens including bacteria, viruses and other foreign substances.
Immune cells known as B cells create antibodies when the body is exposed to a pathogen, such as during an illness or after vaccination, and these antibodies can recognize and attach to antigens, or components, of the pathogen. By neutralizing or removing the pathogen, this binding aids in preventing damage to the body.
Other immune cells, such macrophages, can be triggered by antibodies to aid in the removal of the pathogen from the body. Some of the B cells that created the antibodies stay in the body after the virus is destroyed as ‘memory cells’, which can manufacture more antibodies right away if the same disease is encountered again in the future. The immune system’s capacity to mount a quicker and more effective response to recurrent illnesses or booster shots is based on this.
How long does natural immunity last after a COVID-19 infection?
When our bodies encounter a virus like COVID-19, our immune system remembers it and builds up protection against it. According to the National Institutes of Health, certain immune cells and proteins can recognize and eliminate the pathogen if it is encountered again. This creates immunity, which can protect against disease and reduce the severity of illness.
There are several components of immunity that protect us from viruses like COVID-19.
- Helper T cells
- Killer T cells
Antibodies are blood-circulating proteins that may identify and neutralize foreign things like viruses. While killer T cells eliminate infections, helper T cells aid in their recognition.
When the body needs fresh antibodies, B cells produce them. It has been discovered that those who recover from COVID-19 possess all of these elements. What this means for the immune response and how long immunity lasts, though, is not yet understood.
Contrary to popular belief, a natural infection does not offer long-term protection against COVID-19 according to a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center.
It is difficult to estimate how long the protection will persist against the virus variants, as the protection gradually declines with time.
Studies show that immunity to the viruses that cause the common cold begins to diminish after roughly a year, and new infections can develop later on. The coronavirus that causes COVID-19 is identical to those viruses.
It’s difficult to say how long natural immunity lasts because COVID-19 continues to evolve into new versions.
How long does vaccine-induced immunity last?
Your body will have T cells and B cells that can identify the virus and fight it in the future once you’ve received the full dose of the vaccination. This is comparable to how our body handles built-in immunity.
But, after vaccination, the body needs a few weeks to produce these T and B cells. Up until your body is able to provide protection, there is still a danger of contracting the COVID-19 virus during this time.
The Pfizer and Moderna vaccines, according to a professor at the Johns Hopkins Bloomberg School of Public Health, start to work well two weeks after the initial injection. The second dose then intensifies the immunological response, making the interval between the second and third doses of increased immunity shorter.
T cells and B cells defined
T cells and B cells are both types of white blood cells that play important roles in our body’s immune system.
White blood cells called T cells, sometimes referred to as T lymphocytes, oversee spotting and eliminating foreign invaders like viruses and bacteria that have made their way into our bodies. They function by identifying certain marks, known as antigens, on the outside of these invaders, which then mobilizes other immune cells to attack and eradicate them.
T cells have memories, allowing them to ‘remember’ how to fight invaders should they reappear in the future.
A white blood cell called a B cell, on the other hand, produces antibodies, which are proteins that can recognize and attach to antigens on foreign invaders. When an antibody binds to an antigen, it can aid in identifying the invader so that other immune cells can kill it.
Like T cells, B cells have a memory, but this memory allows them to promptly make antibodies if they encounter the same antigen in the future.
Overall, T cells and B cells work together to provide our body with a powerful defense against foreign invaders, helping to keep us healthy and protected from infection.
Does testing positive for COVID-19 antibodies mean you are immune to COVID-19?
A person who tests positive for COVID-19 antibodies has likely already been exposed to the virus, and their immune system has produced antibodies to combat it. This does not imply that the person is invulnerable to COVID-19, though.
Depending on the individual, COVID-19 antibodies may offer varying degrees and lengths of protection. Some people may experience a robust immune response that lasts for a long time, while others may experience a weaker response that deteriorates with time. What’s needed to watch out for is that new virus types might be able to avoid the immune response brought on by earlier infections or immunizations.
It is still feasible for someone who has tested positive for COVID-19 antibodies to contract the virus once more, especially if they are exposed to a new strain of the virus or if their immune system has gotten progressively less effective over time.
To lower their risk of infection and transmission, people should continue to practice preventive behaviours like wearing masks, engaging in social distance and receiving vaccinations.
Does COVID-19 immunity protect against newer strains of the virus?
As we depend on antibodies for protection against reinfection, there is this big question whether such immunity protects us against new strains of virus as well.
The majority of COVID-19 survivors have antibodies to the virus. But there is no proof that doing so will shield them from future exposure to the virus or interaction with a different strain of it.
Those who have previously had COVID-19 may contract the virus once more and spread it to other people. Compared to the previous dominant strain, Delta, Omicron seems to carry a higher risk of reinfection. Reinfections are becoming more frequent as immunity deteriorates over time and new variations emerge. Some people may become infected again within three months or less.
Why vaccines and boosters matter
How effective are vaccines and why do we need booster shots for COVID-19? Do they really matter and work hand in hand? How does a booster shot work?
An additional dosage of a vaccination is given to a person who has already had the initial set of doses. This is known as a booster shot or booster vaccine. The primary goal of the booster dose is to strengthen and prolong the previous vaccination’s protective effects.
Your immune system is exposed to a tiny, weak or dead version of the virus or bacteria that the vaccine is meant to defend against when you receive the vaccination. Your immune system can identify and remember the pathogen thanks to this exposure, making it easier for it to create an effective defence and fight it off the next time you are exposed to it.
But over time, your immune system can start to forget the pathogen, and the first vaccine’s protection might start to wear off. A booster shot can be useful in this situation. A booster shotIt helps your immune system remember what it needs to be on the watch for and helps it ramp up its defences once again by giving it further exposure to the weakened or dead virus.
Booster shots can be particularly important for certain vaccines that may lose their effectiveness over time. They may also be necessary for vaccines that protect against emerging variants or strains of a virus that weren’t included in the initial vaccination.
On the other hand, vaccines offer a high level of protection against fatal sickness and serious illness. When it comes to blocking the virus’s acquisition and spread, they are not impenetrable. Vaccinated people may still be at risk of contracting the virus, sometimes known as a breakthrough infection, in areas with low vaccination rates and high infection rates.
We might require booster shots at regular intervals for the next few years, given the extremely contagious nature of emerging virus varieties. It might also be a good idea to update the vaccination strain during this time as it ‘is doubtful that the original strain would reappear since it’s on the verge of extinction. This would make it possible to guarantee that the vaccine offers the best defence against both current and future viral strains.
The effectiveness of COVID antibodies can remain for several months following exposure to the virus or vaccination, according to studies, but it depends on the individual. While some people’s antibody levels may remain stable for a year or longer, others may go through a more rapid reduction. This implies that a person may still be at risk of contracting COVID-19 even if they have already been exposed to it or have received a vaccination against it.
To retain immunity against the virus due to the emergence of new variations, it is increasingly crucial to track antibody levels and think about booster doses. Ultimately, research into the durability of COVID antibodies is still underway, and it’s critical to keep up with public health practices like using masks and avoiding close contact with others to help slow the spread of the virus.