25 August 2020

The next stage of the race

The race for the COVID-19 vaccine

Carlos Coelho (text, graphics), Radio Liberty

The world is looking for a way to deal with the COVID-19 pandemic as quickly as possible. More than 170 vaccines are currently being developed in universities and laboratories in different countries. Some of them are already being tested on humans.

It usually takes many years to develop and test a vaccine before it enters clinical practice. However, political and economic pressure forced scientists to accelerate the development of a vaccine against COVID-19.

Many breakthroughs have already been reported along this path, but it will be some time before the world receives an effective and safe vaccine.

Why do we need vaccines?

The human body often develops lifelong immunity after a disease. However, some diseases lead to serious complications and even death. The purpose of the vaccine is to give the body the opportunity to meet with an antigen that will trigger an immune response, but will not lead to disease. If a real virus subsequently enters the body, it will be blocked or destroyed by the immune system.

Vaccine development cycle

Before starting clinical use, vaccines go through several stages of development:

  • Research stage
  • Preclinical stage
  • Clinical trials
    – First phase: small groups of people receive the vaccine; 
    – The second phase: the trials are expanding, the selection of volunteers is becoming more specific; 
    – The third phase: the vaccine is tested on thousands of people, its effectiveness and safety are checked 
  • Evaluation and approval by regulatory authorities
  • Production
  • Quality control

As of August 17, 2020, the World Health Organization (WHO) is tracking the development of more than 170 vaccines worldwide.


Russia is pulling away

Recently, Russia announced the start of mass production and vaccination of the population with the drug "Sputnik V". According to some scientists, the development of this vaccine was not completely transparent and important safety measures provided for in Phase 3 could have been missed during the tests. The developers probably experienced a lot of political pressure to be the first to register the vaccine.

One of the main reasons for the concern of the international scientific community in connection with the Sputnik V vaccine is associated with the risk of "antibody-dependent amplification of infection" (ADE): the virus can use antibodies produced with the vaccine to penetrate cells. This can aggravate the disease of re-infected people. As a rule, this effect is detected during the 3rd phase of clinical trials.

How immunity is developed

When the body detects foreign substances – for example, viruses or bacteria – the immune system tries to recognize pathogens and neutralize them. B-lymphocytes produce antibodies that attach to specific antigens (an antigen is a molecule or molecular structure on the outer shell of a pathogen), and T–lymphocytes destroy infected cells, preventing the replication of the virus.

Antibodies can remain in the body for months or even years – in case the body has to fight the same pathogen again.

The human immune system learns to recognize pathogens – for example, COVID-19. Here's how it happens:


By August 2020, a total of 218 vaccine candidates had been investigated, based on 10 different technology platforms:


Here's how some of the vaccines being developed work:

Antiviral vaccines

Many existing vaccines are made using the virus itself. This method requires strict security controls.

(A) Weakened virus vaccines: the virus is weakened by gradual mutation during controlled infection of human or animal cell cultures.

(B) Vaccines based on deactivated virus: the virus is made safe by acting on it with chemicals or heat.


Vaccines based on the viral vector

Molecular biologists use viral vectors to deliver antigens to cells. Viruses used as vectors are prepared in such a way as to minimize the risk of infection.

(A) Vaccines based on a replicating viral vector provoke an immune response. The coronavirus spike protein gene is placed in the viral vector and injected into the body.

(C) Vaccines based on a non-replicating viral vector are mainly used to enhance immunity in those who are already infected with the virus.


Nucleic acid-based vaccines

Nucleic acid–based vaccines are a relatively new technology that is still being developed and studied. According to some reports, vaccines based on RNA and DNA plasmids have the potential to become safer and more effective than vaccines made using other technologies. Synthetic methods are used to create RNA vaccines, biological material is not used. Other advantages of nucleic acid–based vaccines include the simplicity of the vector and the efficiency of its delivery.

(A) The DNA vaccine is based on the electroporation method, by which pores are created in the cell membrane, which simplifies the absorption of DNA.

(C) The RNA vaccine is placed in a lipid envelope, which allows it to enter the cell in the same way as the virus.


Protein-based vaccines

Protein–based vaccines use protein subunits – such as spike proteins, membrane proteins, and empty virus shells - to trigger an immune response to a pathogen.

(A) Protein subunit vaccines give the immune system a specific isolated antigen without viral particles, provoking an immune response.

(C) Virus–like particles – for example, empty virus shells - repeat the structure and behavior of the coronavirus, but do not infect the body, since they do not contain the genetic material of the virus.


When will the vaccine be available?

The Coalition for Epidemic Preparedness Innovations (CEPI) said in April that the vaccine could become available in early 2021 under the emergency protocol.

Forty countries promised WHO in May 2020 assistance totaling $ 8.1 billion for the early development of a vaccine. In addition, WHO has developed a system that allows simultaneous transparent evaluation of promising developments undergoing clinical trials. This system brings together international organizations, universities, multinational pharmaceutical companies and government agencies to work together on a coronavirus vaccine.

This project assumes that comparing hundreds of potential vaccines with the same criteria will allow you to choose the best option.

According to WHO, more than 150 countries are developing a vaccine against the new coronavirus.


Who will get the vaccine first?

Government organizations and private companies invest tens of billions of dollars in vaccine development, so it is not surprising that doubts arise about the fair distribution of an effective vaccine.

The UK has invested $79 million in the development of the Oxford University vaccine in exchange for 30 million doses. The multinational pharmaceutical company AstraZeneca participates in this development, which has promised the United States 300 million doses in case of investments worth $ 1.2 billion.

The European Union has launched the European Vaccine Strategy vaccine development program, worth $2.3 billion, to provide access to the vaccine to all members of the union.

Residents of economically developed countries are likely to be the first to get access to the vaccine, while in poor and densely populated countries that will not be able to pay for vaccines, they will be less accessible or not at all.

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