And what’s the difference between each of these unique vaccines? Read more to find out.
by Kiersten Ngeow
It was barely six months ago when the world was overwhelmed with Covid-19 and had no recourse on how to combat this epidemic. In January 2021, according to the CDC, the US had over 95 thousand deaths, and the rate was increasing. Different mutations of the virus were also wreaking havoc worldwide, some allowing the virus to transmit many times easier than before. This year started with the deaths of thousands, and now fast forward to June 13th, 2021; according to the New York Times, the US had only 95 deaths.
The difference is evident – we now have multiple vaccines that can effectively control the spread of the virus. Vaccines generally take 5-10 years to develop; for example, the HPV vaccine that prevents cervical cancer took 7 years to develop. In comparison, the Covid-19 vaccines had been developed in record time – from start to emergency use approval in barely 9 months! Making the Covid-19 vaccine to be the first to be developed so quickly, let alone multiple types!
The three major types of Covid-19 vaccine are the messenger RNA or mRNA-based Pfizer and Moderna vaccines and the Adenovirus-based Johnson & Johnson (J&J) vaccine. But which one is right for you?
You should choose an mRNA vaccine (Pfizer/Moderna)
The mRNA vaccines are based on the latest technology that uses a modified RNA fragment encapsulated in a lipid enclosure to coax our cells to produce the spike protein seen in the SARS-COV-2 virus. This trains our immune system to recognize the spike protein and generate antibodies to neutralize these foreign objects. The RNA fragments are very safe as they never modify the host cells’ DNA but coax the RNA to produce the spike proteins.
The mRNA vaccines have never been used before – the Covid-19 vaccine is the first application of this technology. Because the RNA fragments are extremely fragile, the vaccine is stored in an ultra-cold freezer between -80°C and -60°C, then “defrosted” to -25°C to -15°C before use. Once defrosted, it must be used within 2 weeks. The newer Moderna Covid-19 vaccine is hardier; it can be stored between -15°C and -50°C, allowing regular medical freezers to be used to keep the vaccine.
The mRNA-based Pfizer vaccine is also the only vaccine approved for those under 18, and teenagers have no other vaccine choice. But for those 18 or older, which vaccine is right for you?
It is hard to ignore the benefits of mRNA-based vaccines – it does not invade our DNA. It has significantly fewer adverse reactions and has a high efficacy of around 94%, meaning, on average, someone fully vaccinated only has a 6% chance of catching the Covid-19 virus. However, the mRNA vaccines need an unbroken cold chain to ensure potency – once these mRNA vaccines experience higher temperatures, the clock starts ticking, and they will become useless quickly. The mRNA vaccines also require two shots to ensure complete vaccination, separated by 3-4 weeks. Thus, double the time and effort needed for anyone choosing the mRNA vaccines.
You should choose the adenovirus vaccine (J&J)
Unlike the mRNA Covid-19 vaccines, the J&J Covid-19 vaccine uses a well-understood adenovirus vector virus to deliver the vaccine into human cells. The mechanism is also different from the mRNA vaccines. Where the mRNA vaccines never enter the nucleolus of human cells and thus, does not modify our DNA, the adenovirus vector must enter the nucleolus and modify human cell DNA to produce the spike protein that trains our immune system.
The adenovirus vector vaccines are extremely hardy – it is encased in a virus shell that allows the vaccine to be stored at normal refrigerator temperatures – between 2°C and 8°C, it can be easily transported and stored at pretty much every medical facility.
Additionally, the J&J vaccine is much less fussy – it does not need a freezer to store and transport. Thus, it can be relocated to any medical location that has a regular fridge. Best of all, it only requires a single dose, halving the effort needed in comparison to the mRNA vaccines. This vaccine is perfect for remote and rural locations, where people might have to travel many miles to get their shot. The J&J vaccine also has the benefit of being well understood – the Adenovirus is simply a common cold virus modified to carry instructions to create the SARS-COV-2 spike protein.
However, the J&J vaccine had some serious adverse reactions – as of May 13th, 2021, three people had died of a blood clot that was linked to the vaccine, and many more were hospitalized. However, this represents only 28 cases out of about 8.7 million vaccinations.
On April 23rd, the CDC halted the use of the J&J vaccine out of caution, but it has since been resumed. The efficacy of the J&J virus is also lower, at around 72% in trials in the United States, but has 85% efficacy against severe Covid-19 globally.
So, in short, which vaccine should one be getting? mRNA vaccines for safety and better efficacy, or the J&J adenovirus vector vaccine for convenience?
Personally, as a teenager, I was only able to receive the Pfizer vaccine. With any of these three vaccines, you can experience side effects, and mine were headaches, fatigue, and swelling on my arm. These side effects occurred because my immune system reacted towards the vaccine and was creating antibodies. But, within a few days, they disappeared.
The rest of my family members (apart from my older brother) received different vaccines. When the vaccines were newly released earlier in the pandemic, it was harder to schedule an appointment to become vaccinated. As a result, my parents drove for 2 hours to receive the J&J vaccine. Since it was a one-shot vaccine, my parents didn’t have to travel miles to receive a second shot. My sister on the other hand received the Moderna vaccine. For her, receiving this vaccine was out of convenience as it later became available in her area.
Regardless of which vaccine you choose, the most important fact is to be vaccinated as soon as possible. The consequences of delay are deadly – Covid-19 has hospitalized more than a million in the United States and killed over six hundred thousand. In comparison, the 28 hospitalizations and 3 deaths due to the J&J vaccine are minuscule.
Herd immunity – when a large population gains protection against a specific disease, it is vital to reducing the spread of Covid-19. Thus, no matter which vaccine you choose, whether it’s Pfizer, Moderna, or J&J, these vaccines hold the key to protecting us all from Covid-19.