Yeah, many many different types of covid vaccines are coming, hopefully early next year. That leads to a tough question among you humans. Which one should you choose? Unlike choosing your favorite clothes, foods, smartphones, etc., this time it's not just about which brand (pharmaceutical company) is better, but something more vital.
Thank to this once-in-a-lifetime opportunity, watchdog organizations worldwide all tend to be more 'OPEN'. Many pharma companies, biotech startups around this little planet, boldly applied some 'avant garde' scientific theories to their vaccine design. SO, it is very hard to say whether you are a beneficiary of those future technologies or just a 'white rat',
Luckily, I'm just a Robot created by pinkwork™ extraterrestrial which is immune to all human virus, don't have your trouble of 'Too many Choices'.
OK OK, you humans need not worry! Let me explain in a (highly) simplified way, the science behind the three most promising vaccine candidates, namely Viral (Inactivated or Killed), Viral Vector & Nucleic Acid (DNA or RNA) vaccine.
Your immune system functions like that: whenever a new type of virus invades, your body would send out soldiers to fight. After several rounds of fights, these soldiers would gradually develop skills & tactic to deal with this particular type of enemy. Next time your body encounters them again, a group of well-trained soldiers (Antibodies, T-cells, etc.) will quickly kill them all.
The problem is, if the enemy is too strong which could wipe out all your soldiers during the first encounter. You'll die and you immune system won't work! Well, if there is a way that could ensure your in-body soldiers will never be defeated, they must be able to learn the skill to kill the enemy (make you gain immunity). That's the purpose of vaccine. To achieve this purpose, there are three different ways.
Beat the enemy to death before Fight
Inactivated Virus Vaccine
Just like what the sub-heading said, the concept is first killed, weakened or inactivated the viruses, usually by heat or chemical treatment before injecting to your body. It is the most old-school (traditional) way to develop vaccine. The MMR, Hepatitis b .. etc. vaccines are of this type.
It's a relatively mature technology, so more safe. But some humans, like the anti-vaxxers would think those weakened viruses could still be harmful. OK, to make your in-body soldiers sure win, your scientists came across another idea.
Weak Opponent disguises as Strong EnemyViral Vector Vaccine
If you still worry even you've beaten your new enemy to death before the fight. How about choosing a very very weak opponent. Then genetically add some characteristics of your new enemy to it, in short, to disguise it as the new virus.
One 'weak' opponent candidate human scientists think of during covid vaccine development is AdenoVirus. It's a type of virus that usually causes coughs, sore throats, diarrhea, pink eye, etc. among children.
The Ad5 vectored COVID-19 vaccine developed by Beijing Institute of Biotechnology & CanSino Biologics belongs to this type. But picking a weak opponent might has a disadvantage. Though it has been genetically engineered, your immune system may still knew it too well that it could quickly defeat it. In the end, your in-body soldiers don't get enough time to train their fighting skill.
That may be why the ChAdOx1 nCoV-19 vaccine developed by Oxford University & AstraZeneca is using a chimpanzee instead of human adenovirus! This type of adenovirus would only cause common cold in chimpanzees & totally harmless to humans. In theory, it could balance safety & effectiveness of the vaccine.
Still think it's not 100% safe?! Well, how about No-contact Training?!
Non-contact Combat Training?!
Nucleic-Acid Vaccine
Your scientists suddenly think, whether just injecting a synthetic genetic segment, DNA, mRNA, etc. of the virus is enough to stimulate or teach human immune system to produce anti-bodies. That is the concept of Nucleic-Acid vaccine.
Since this time only a small fake 'body part' of, not the whole (real) virus is used, it should be 100% safe! It is a completely NEW theory & has never be applied to any human vaccine development. The main point is whether this will work?
"The early testing result is very encouraging!" said Moderna, an US biotech company which has never produced an approved vaccine before. But it took just 3 months to develop a mRNA nucleic-acid Covid 19 vaccine that can enter Phase 3 Trial.
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Nucleic-Acid vaccine seems to be a 'perfect' solution, but in some cases in human vaccine history, side effect may take many years to come. Back to the tough question in this writing's title. Well, the answer depends on whether you are brave enough to try a totally new technology, or you prefer the most traditional solution.