Since I have a few options for vaccination: Pfizer, AstraZeneca or Sputnik V, I decided to figure out as much as possible about all currently existing vaccines and share my findings with you in case you are still confused about how many and what vaccines are available in your country and the world, what are the main differences between vaccines and what exactly is needed to create a vaccine in general. And most importantly, you will find here a detailed map, where, having selected your region, you can find extended information about all vaccines being developed in your region and which of them are currently available for your vaccination.
According to the COVID-19 Vaccine tracker, as of May 24, 2021, more than 200 vaccines are in development, 120 of them are in human trials (phases I-III), 33 vaccines are in Phase III, 16 vaccines have been approved by at least one country, and only 6 are approved by the World Health Organisation (WHO). As for the European Union, they have currently approved 4 vaccines (more details in table 2).
Firstly, some general information to help you better understand what kind of “creatures” these vaccines are. 8 various platforms are used to develop vaccines against SARS-CoV-2 (the difference between COVID-19 and SARS-CoV-2 can be found at the end of this article). These include both traditional vaccine production technologies and innovative methods such as vector-based platforms, as well as DNA or RNA-based. In table 1 below you can find a classification of all possible types of vaccines against covid-19.
Table 1. Classification of vaccines against covid-19.
|Type of Vaccine|
|Whole Vaccines|| |
|This vaccine is made by deactivating the virus during the manufacturing process. An inactivated virus cannot cause disease, but the inclusion of immunostimulants in the vaccine helps induce an immune response.|
|The virus or bacteria are functional/alive but have been weakened so they can replicate in the body several times and trigger an immune response without causing disease.|
|Component vaccines||Non-Replicating Viral Vector Vaccine||This vaccine uses a safe virus to deliver specific sub-parts (proteins) of germ to trigger an immune response without causing disease.|
|Replicating Viral Vector Vaccine||The technology for obtaining this vaccine is the same as that of a non-replicating vector; however, due to the ability of this vector to multiply, small doses are enough to develop immunity.|
Protein Subunit Vaccine
|For the production of this vaccine, a very specific part of a virus or bacterium is used, in this case, a protein of a pathogen, which the immune system must recognise and give an immune response.|
|Virus-like particles Vaccine||Similar to the aforementioned subunit vaccine, but uses a protein that mimics the pathogen itself.|
|DNA-based Vaccine||Containing the code for the synthesis of specific proteins, which our body’s immune system must recognise and give an immune response.|
|RNA-based Vaccine||The active part of this vaccine is ribonucleic acid (usually matrix, mRNA), which encodes a protein characteristic of the pathogen.|
For those who prefer visual context over text, here is a picture with a classification of platform types for vaccines (graph 1).
Secondly, it was interesting for me what is the most popular type on which base the pharmaceutical companies around the world are developing their vaccines. To figure it out, I took information from this source (https://covid19.trackvaccines.org/vaccines/), calculated the number of vaccine candidates by type of their technology platform and put results in table 2 below.
Table 2. The number of vaccines by type.
|Non-replicating viral vector|| |
Replicating viral vector
As you can see from the table above, the most popular type is the Protein subunit platform. I was wondering why, and here is an answer. The popularity of this platform is primarily due to the safety of such vaccines. Subunit vaccines have “technological safety” because no live virus is used at any stage of their production, and the vaccine itself contains only viral proteins.
In second place in popularity are RNA vaccines (nucleic acid vaccines), they are very promising. This area of vaccinology appeared relatively recently and is actively developing. The production of such vaccines is one of the simplest, but the technologies for the delivery of genetic material into the cells of the body are still not well developed, which has hindered the active introduction of Genetic vaccines so far. Never before until now in modern history has a nucleic acid vaccine been used in clinical practice in humans.
The least popular platform for producing vaccines is Live-attenuated. This is due to the sufficient danger of the virus. Although the virus in the attenuated vaccine is weakened, there is a possibility that it will return to the wild type, which could lead to an outbreak of the disease during vaccination. All this leads to the need for regular researches to study their genetic stability. In addition, the technological production of Live-attenuated vaccines is not rapid compared to the production of Subunit vaccines or RNA vaccines.
As an example of such a rapid production of RNA vaccines, CureVac N.V., a German pharmaceutical company, uses a portable automatic printer (“RNA micro-factories”). This project is carried out in cooperation with Tesla.
Thirdly, I have collected information from various sources on the first 12 vaccines that have been approved by many countries (and some have received WHO and EU approval) and are currently being used for vaccination. There is sometimes conflicting information on the effectiveness of some vaccines on the Internet, so in table 3 below I put figures from the most reliable sources (from my point of view of reliability).
Table 3. 12 most popular vaccines used in the world (May 2021).
|Country||Mechanism||Number of doses||Interval between doses||Overall efficacy, %|
|AstraZeneca||UK||Non-replicating Viral vector|
|Janssen||USA||Non-replicating Viral vector|
|Covishield (AstraZeneca+)||India||Non-replicating Viral vector|
|Sputnik V||Russia||Non-replicating Viral vector|
|CanSino||China||Non-replicating Viral vector|
Important: all numbers are as of May 2021.
A map of countries where you can find detailed information on all vaccines that are being developed in the world, and which vaccines are available for vaccination in a particular region, is located here: https://covid19.trackvaccines.org/trials-vaccines-by-country/#approval-map.
Finally, when I collected all the information that I was interested in, I wondered what exactly it takes to create a vaccine. Here is what I found out. In general, vaccine development is divided into 5 phases: preclinical trials, then 3 phases of clinical testing and approval by the regulator, after which the vaccine is transferred to production and logistics.
Graph 2. Source: photo stock on the Internet.
Take a look at table 4 below for more understanding of what each stage of clinical trials is about and how many vaccines are currently being developed at each stage.
Table 4. Stages of clinical trials.
What is the phase about?
The number of vaccines that are developing, May 24, 2021.*
|How will this vaccine work?|
This intensive research phase is designed to look for natural or synthetic antigens – foreign substances that trigger an immune response in your body – that trigger the same response as a real virus or bacteria.
|Phase I||Is it safe? And what is the right dose?|
The first testing in a small group of adults, typically 20 to 80 people, to assess its safety and measure the immune response it elicits, as well as determining the most effective dose and improving the safety of the vaccine.
Several months or even a year
|Phase II||How effective is the vaccine?|
At this stage of clinical trials, more volunteers are receiving the vaccine to study its effectiveness.
|Phase III||Is it ready for the world?|
Regulatory approval and licensure.
After a successful Phase III trial, vaccine manufacturers apply with regulatory authorities.
Years to decades
|Phase IV||Will it stay safe down the road?|
Even after a vaccine is approved and licensed, regulators continue to be involved in monitoring production; inspection of industrial premises; and testing vaccines for efficacy, safety and purity.
* These numbers I took from this source as of May 24, 2021: https://covid19.trackvaccines.org/vaccines/.
** The number of vaccines approved in at least one country. However, most of them are still undergoing Phase III.
However, I didn’t find definite answers for several questions such as:
- How long do vaccines prevent covid-19? For Pfizer, it is a minimum of 6 months, but there is no information for others.
- Will people who have had covid-19 have protective immunity against this virus? If yes, how long?
- How strong will the current vaccines protect against the UK, South African, Brazil and Indian variants?
The presumptive answer to the first question is six months to two years after the first full vaccination. After this period has passed, you will probably need to give a booster shot. Why? There are several reasons for re-vaccination:
- your immune system can just forget things over time.
- the virus is mutated and nobody knows which variant will be next in a row (after the UK, African, Brazilian and Indian variants).
In addition, the degree and duration of protection afforded by a vaccine may vary from person to person, depending on the individual characteristics of a particular person.
To sum up, all of the above makes me feel like until more is known, even after vaccination, I will keep my precautions while this ‘creature’ is still actively spreading around the world. Probably, now is still not the best time to relax, but as we know, time flies by and human beings easily get used to everything, and in a few years, I believe, we will almost forget about this nightmare.
Disclosure: This is not a scientific article. These are just pieces of information that I have collected from various sources (most of them are official) and presented in a format convenient for me and, I hope, for readers.
PS. COVID-19 = ‘CO’ stands for ‘corona,’ ‘VI’ for ‘virus,’ ‘D’ for disease and 19 indicates the year it was discovered. SARS-CoV-2 = Severe Acute Respiratory Syndrome CoronaVirus 2 – is actually the virus that causes COVID-19 (the disease).
The main online sources I used: