Therapeutics

• Author: Dumbrava, Costica
• Pages: 7-12

Lifting coronavirus restrictions

7

3. Therapeutics

3.1. Vaccines

A vaccine is key to tackling the Covid-19 pandemic, as it would provide healthy people with

immunity from infection (though it would not cure the disease in infected people). The virus that

causes Covid-19 is roughly 80 % identical33 to those that caused the outbreaks of SARS and MERS,

which may give researchers a good headstart in developing therapeutics. However, early evidence

suggesting that the virus may be unlikely to mutate significantly,34 making it an easier target, has

been challenged.35 Moreover, the development of a vaccine faces a number of great challenges,

such as not having sufficient knowledge of the virus (knowledge gaps), the need to complete

adequate testing of vaccines to ensure safety and, once a vaccine proves effective, making sure that

there is a sufficient amount of it to enable its swift and fair distribution across the world.

3.1.1. How do vaccines work?

When a virus enters the body, it seeks to take control of cells in order to replicate and spread

throughout the body. Generally, vaccines work by exposing the body to an antigen that will provoke

an immune response, which will then block or kill the virus when the vaccinated person becomes

infected.36 Vaccination takes advantage of the body's immunological memory, which allows it to

'memorise' the specific features of a virus in order to recognise and fight it later in life (adaptive

immunity).37 It must be noted that vaccines do not always provide full protection against the viruses

they target, nor do they always eliminate the risk of spreading such viruses.38 For example, influenza

vaccines mainly reduce the risk of contracting the disease and the likelihood of experiencing severe

symptoms.

There are

a number of types of vaccines

39

targeting Covid-19 that are currently in development:

vaccines using the virus itself, in a weakened or inactivated form (similar to measles and polio

vaccines); viral-vector vaccines, which use other weakened and genetically engineered viruses to

prompt the body to produce coronavirus proteins; nucleic-acid vaccines, which use genetic

instructions (in the form of DNA or RNA) for a coronavirus protein to prompt an immune response;

and protein based vaccines that inject harmless elements of coronavirus proteins (particles or shells)

directly into the body to mimic the virus and trigger immune response.

Vaccine candidates are typically tested in several phases, allowing for the gradual expansion of the

number of trial participants from a few dozen (phase 1) to thousands (phase 3). Advancement to

subsequent phases requires specific evidence-based approvals.

33 S. Weston and M. B. Frieman, 'COVID-19: knowns, unknowns, and questions',

mSphere

, 2020.

34 J. Corum and C. Zimmer, 'How Coronavirus Mutates and Spreads',

New York Times

, 30 April 2020.

35 B. Carey and J. Glanz, 'Mutation Allows Coronavirus to Infect More Cells, Stu dy Finds. Scientists Urge Caution',

New York Times

, 12 June 2020.

36 E. Callaway, 'The race for coronavirus vaccines: a graphical guide',

Nature

, 28 April 20202.

37 A. Rothstein, 'Vaccines and Their Critics, Then and Now',

The New Atlantis

, No. 44, 2015.

38 H. Branswell, 'The world needs Covid-19 vaccines. It may also be overestimating their power',

STAT

, 22 May 2020.

39 Callaway, (The race for coronavirus vaccines: a graphical guide) see footnote 35 (above).