By Hermione Cabie Santos
On August 23, 2021, the Food and Drug Administration finally granted its first approval of a COVID-19 vaccine. Pfizer-BioNTech’s mRNA vaccine, under the proprietary name COMIRNATY, reached a significant milestone in the pandemic’s history.
Less than a year after the issuance of emergency use authorization (EUA) to COVID-19 vaccines from pharmaceutical giants, approximately 33 million doses have been administered daily across more than 180 countries, including the Philippines, in the biggest vaccination campaign in mankind’s history.
In Canada alone, roughly 53.7M doses have been given with over 25M people being fully vaccinated. A hefty 73% of the total population already received a single dose.
In comparison, neighbouring United States of America has given 374M doses, with more than 175M people fully vaccinated. About 63% of the total population has received a single dose.
To date, about 40% of the world population has received at least one dose of the COVID-19 vaccine, with approximately 5B doses administered globally.
With increasing vaccination confidence (yes, despite valid concerns with vaccine hesitancy) what could this mean in the race against the emergence of variants?
The World Health Organization and the international scientific community have been on guard for the emergence of COVID-19 strains and the biological significance of these.
Since late 2020, the emergence of variants led to the designation of these viral strains into, namely: ‘variants of interest’ and ‘variants of concern’. The designation criteria were based on how quickly the variant spreads infection, presenting symptoms, disease severity, genetic changes that may affect transmissibility and any effect on current public health measures.
In addition, to assist in the public discussion of these variants, the WHO convened a group of experts to come up with easy nomenclature that will prevent confusion or stigmatization of these entities.
Currently Designated Variants of Concern (VOC):
ALPHA (B.1.1.7 Pango Nomenclature): First documented in United Kingdom, September 2020
BETA (B.1.351): First documented in South Africa, May 2020
GAMMA (P.1): First documented in Brazil, November 2020
DELTA (B.1.617.2): First documented in India, October 2020
Currently Designated Variants of Interest (VOI):
ETA (B.1.525): Early documentation in multiple countries, December 2020
IOTA (B.1.526): First documented in the United States of America, November 2020
KAPPA (B.1.617): First documented in India, October 2020
LAMBDA (C.37): First documented in Peru, December 2020
MU (B.1.621): First documented in Colombia, January 2021
Certain variants spread notoriously and quickly than others, which have led to spikes in cases of COVID-19 in different parts of the world.
Why Are There COVID-19 Variants?
Whenever a virus is allowed to infect a population and jump from one individual to another, there is always the inherent likelihood of the virus mutating. When the virus spreads, the virus replicates. The more it replicates, the more opportunities it is allowed to mutate.
The knowledge of the virus mutating may cause panic and fear.
However, viral mutation is quite normal, especially true of viruses which have RNA as their genetic material (e.g. influenza virus and SARS-CoV-2).
Viruses contain a genetic material (either RNA or DNA) that is covered by a coat of protein. However, viruses cannot replicate on their own. They need to enter a host cell, often via the mouth or nose, before it is able to make copies of itself and infect other cells and/or infect another host. In the process of copying itself (replication) errors are encountered in the process. Think of it as a news report being encoded with typographical errors. If you encode the news report one million times, you have a million opportunities to commit typographical errors.
In viral replication, this error is what we call a mutation. This mutation allows for the emergence of a variant.
While the reality of viral mutation appears overwhelming, it is important to understand that on one hand, the resulting mutation may impair the virus, causing poorer transmission and replication. On the other hand, the mutation may allow the virus to transmit and replicate better (in which case it becomes a dominant variant that ends up being closely monitored). This explains why in certain populations, a certain variant becomes predominant, while others are almost unheard of.
In other words, viral variants do come and disappear, but other variants persist longer than others.
Noteworthy is that SARS CoV-2 variants contain alterations (small changes) to
the ‘spike protein’ (particularly on its RBD domain) which is highly responsible for the attachment of this coronavirus to human cells and the site mostly recognized by neutralizing antibodies.
Will COVID-19 Vaccines Offer Protection to Variants?
First, it is beneficial to understand that not all vaccines produced will provide sterilizing immunity. This is the type of immunity that completely prevents a pathogen (like SARS CoV-2) from infecting the body and causing disease.
Second, some vaccines will provide effective immunity, where the risks of symptomatic or severe disease (and possibly even death) are greatly reduced.
However, a fully vaccinated person can still be a carrier.
Third, the body’s immune response (the protective response your body mounts against natural infection or vaccination) relies on the concerted efforts of your memory B cells, antibodies and helper T-cells and killer T-cells.
Simply put, our immune system protects us from different angles. A variant may escape certain aspects of antibody protection, but will not evade the protection from the body’s helper/killer T cells.
According to the National Institutes of Health, SARS CoV-2 specific CD8+ T-cell response remained intact and able to recognize virtually all mutations in studied variants.
Needless to say, we need to continue implementing public health measures in the prevention of COVID-19 infection and severe disease.
Breakthrough infections (infections even from vaccinated individuals) may still occur, as the available COVID-19 vaccines do not provide 100% sterilizing immunity.
Vaccine and SARS CoV-2 Takeaways:
COVID-19 variants are expected.
We can help slow down the emergence of new ones by reducing the spread of infection (to humans and even animals) using public health measures already in place (social distancing, proper masking and respiratory hygiene, among others).
Getting vaccinated against SARS CoV-2 remains a powerful arsenal in promoting public health.
COVID-19 vaccines provide effective protection from symptomatic infection, hospitalization and death.
The whole world awaits the developments and breakthroughs that will secure our victory against this viral race with moving targets.
For now, Pfizer-BioNTech’s COMIRNATY and FDA-authorized COVID-19 vaccines will suffice in providing an effective degree of protection against current variants and, hopefully, future mutations.
References:
Government of Canada National Vaccination Coverage
Our World in Data: Statistics and Research (September 4, 2021 Report)
National Institutes of Health (Advisory on T-Cell Recognition of Recent SARS CoV-2 Variants)
World Health Organization (Effect of Virus Variants on COVID-19 Vaccines)