Coronavirus: How long would immunity from COVID-19 vaccines last?

Immunity against coronavirus holds a lot of crucial keys in our fight against the pandemic. Not only are vaccines proving to be a defensive bullet against COVID-19, they are also quite important in driving community-wide herd immunity, which will help minimize the risk of coronavirus.

Now, most of the vaccines that have been approved for use boast good efficacy rates and are capable of mounting high immune responses against the SARS-COV-2 virus. However, as we are seeing, the vaccines' efficacy rates have been found to tame down as newer variants of the virus are being discovered. Lowering efficacy, and antibody count is also making them susceptible to breakthrough infections.

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Our immunity is as strong as we are. With no clear information as to how well protected we are, or how far we would be protected from coronavirus, what does it mean for the coronavirus vaccines we have?

Will we require booster shots for additional protection? Or would vaccines need to be tweaked?

Here's all you need to know about the same

Immunity against coronavirus can be built up in two ways, one, by specifically being exposed to the virus and getting infected (i.e., how our bodies fight off the infection and build antibodies) 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.

Variants of the virus which have been circulating since some months ago are feared for their high infectivity and transmission rates. It is also believed that the mutations to the virus allow it to surpass some of the immune defences present in the body, thus lowering the efficacy and protection mounted by the vaccine.

The Delta variant, which is now held responsible for the rapid surge in cases across the world, could be the scariest since it can reduce vaccine-driven immunity considerably. There has also been a rise in the number of vaccinated people catching the infections during the recent wave.

Thus, even as more variants are to appear, there could be chances that immunity generated via vaccines could be impacted. Research is still underway to conclude the same.

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 Pfizer’s 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.

While some vaccines have been proven to be well-effective and resistant, scientists are currently toying on the possibility of providing booster doses of the vaccines for ‘additional; protection.

For example, a study conducted by a group of researchers at Oxford University found that a potential third, booster shot of the Oxford-Astrazeneca vaccine , delivered 10 months after the initial shot could scale up the immune response in a much better way, and provide lasting immunity unlike what is observed with a regular two-dose regime.

Booster shots also provide additional benefits and have been in place for years with most preventable vaccines, such as flu shots. For people who are immunocompromised, or suffer from health conditions that limit the vaccine from working well, having additional vaccine shots can help them safeguard against coronavirus.