Until January 23rd 2021, more than 60 million people around the world got vaccinated with at least one dose of the covid-19 vaccines. While countries are putting more and more effort to vaccinate every member in society in order to protect them and hold back the infection, a lot of things are still foggy. For instance, how long does the immunity gained from vaccines last? Can new variants of the virus resist these vaccines? Can someone get infected by COVID even after getting vaccinated?And how the vaccines currently tested differ? If you're looking for answers , keep reading you’ll find them right here.
1. How long does the immunity gained from COVID-19 vaccines last?
Recently, we’ve been wondering if the immunity gained from
COVID-19 vaccines will last for a long period of time or short period.
After one year of the pandemic spread,
several primary studies over short and long periods have been published.
But these studies are still limited
because of the limited time for upgrading vaccines. According to La Jolla
Institute for Immunology, immune memory against COVID-19 gained from natural
infection lasts for 8 month or more.
It varies from one person to another and it is possible that immune memory gained
after vaccination will be similarly long lasting. To know for sure several
vaccine studies are now being made.
Five month minimum is the immunity memory you gain after vaccination, declared
by U.K. Department of Health.
Some scientists believe that this
immunity will last more than 6 month or perhaps years. Of course, this doesn’t
apply to all people. People with a weak immune memory are at risk of re-infection
of COVID-19 in the future.
2. Can new variants of corona virus resist COVID-19 vaccines?
This is definitely a big concern, as viruses are constantly
changing and sometimes they change a lot that the vaccines are not able to
fight them back. So, it depends on how different the variant become from the
original virus. But that doesn’t mean it’s over. We still can improve vaccines
enough to face the new variants of the virus. With the merge of new variants in
South Africa and UK which spread to other countries, Moderna and Pfizer-BioNTech
declared that their vaccines, are also affective against The South
African and UK variants. Although both of them are currently working on an
additional vaccine to boost protection against the new variants.
3. Can someone re-infect with COVID-19 after vaccination?
The answer is yes, re-infection with COVID-19 is possible
even after vaccination for many possible reasons. The immunity memory after
vaccination takes 2-3 weeks to be activated after the first or second shot
according to the vaccine’s type.
So, it is possible to get infected within these
2-3 weeks before the activation is complete.
Doctors confirmed that the
infection after vaccination would have much lower effects. But still there isn’t a 100% guaranteed
way to stop the infection completely.
Although, Infection spread from vaccinated
person to another would be significantly harder.
4. How the vaccines currently tested differ?
COVID-19 vaccines that are available now or still under development,
are distinguishable according to the different technologies they use. There are
"classic vaccines" that use viral proteins or whole inactivated virus
and "modern vaccines” that have been manufactured using different technologies
than the ones used in classic vaccines.
These new ways enables producing a given viral protein called "spike protein" by introducing a DNA sequence with precise instructions into our body cells. This genetic information are introduced directly into the cell (mRNA vaccines) or through a viral vector that infects the cell without replicating.
Already approved
Pfizer-BioNTech and Moderna vaccines are mRNA vaccines. Whereas Oxford/AstraZeneca
vaccine, the Janssen (Johnson & Johnson) vaccine and the Sputnik vaccine
are viral vector vaccines manufactured by the Gamaleya Institute. All of these
vaccines were tested to prove they’re safe and effective throughout the three
phases of clinical trials.
Messenger RNA: Pfizer / BioNTech and Moderna
Pfizer / BioNTech and Moderna vaccines both are mRNA-based. These
vaccines work by providing the genetic sequence coding for the "spike
protein" of SARS-CoV-2 to our cells. Meaning, the laboratory-synthesized genetic
material contained in these vaccines provide our cells with specific instructions
to produce the S protein.
Our immune system recognizes this protein as foreign once it’s produced and
generates S-specific antibodies and T cells to get ready to fight back the disease
in case of infection by the covid-19 virus.
Viral vector: Oxford / AstraZeneca and Johnson & Johnson:
These vaccines use a harmless inactivated virus to introduce
the needed genetic instructions to produce the Spike protein into our cells. This
harmless virus, or so called a viral vector, were modified to infect our cells without
being able to replicate.
The Oxford / AstraZeneca vaccine is made of a
modified chimpanzee adenovirus that packs the DNA coding for the Spike protein.
The adenoviral vector delivers this DNA fragment when infecting our cells that
way our cells can produce the protein.
Then our immune system will recognizes
it as a foreign protein and will generate antibodies and T cells.
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