I
would like to share here the positive results from one of the promising
SARS-COVID-2 vaccines labelled AZD1222, and explain more about the clinical
trial process.
Currently, more than 140 vaccines for COVID-19 are
in pre-clinical and clinical development, which means that they are being
tested in non-human subjects (cells, mice, rats, ferrets, rhesus macaques,
etc). 10 vaccines are being tested in humans for safety and dosages (this means
in healthy subjects), 8 vaccines are in phase II, which involves testing the
safety in expanded studies. Only 3 vaccines are starting phase III, meaning
large scale efficacy tests. In this phase, the vaccine is tested in thousands
of people separating the volunteers in 2 groups: one will receive the actual
vaccine and the other - the placebo one to determine if the vaccine protects
against the coronavirus. The last step can be a phase IV trial with an even
bigger and diverse group of volunteers and a review of the results by the local
regulatory entity which will evaluate if the vaccine is approved or not for use
in that region. Notice that each country has its own regulatory organization
and some medicines are approved for use in the USA but not in Europe.
Fortunately, there are a lot of different types of vaccines and you CAN NOT put
them all in the same bag!
These vaccines use a different type of virus that
wouldn’t affect humans in a negative way (called a vector) to deliver
coronavirus genes into cells and trigger an immune response.
The British-Swedish company AstraZeneca and the
University of Oxford are working on a viral vector vaccine using a chimpanzee
adenovirus that will expose the coronavirus’ S protein on its surface in order
to trigger an immune system response in the people that will be vaccinated. The
vaccine is in Phase II/III trial in the UK and Phase III trials in Brazil and
South Africa, and it might be ready by 2021. “AstraZeneca” claimed their total
manufacturing capacity stands at two billion doses. This vaccine uses a
different type of virus that wouldn’t affect humans in a negative way (called a
vector) to deliver coronavirus genes into cells and trigger an immune
response.
They reported last Monday the
"encouraging" results from the trial that included 1,077 participants
from 18 to 55 years old (who had not previously tested positive for the
coronavirus). The participant's gender was fairly well distributed, but they
were mostly white. The study was single-blind, meaning patients did not know
whether they received the coronavirus vaccine or the control (a meningitis
vaccine).
They reported that around 70% of the participants
suffered adverse events such as pain, feeling feverish, chills, muscle ache,
headache, and malaise, which were reduced by the use of paracetamol, and there
were no serious adverse events related to the vaccine. The T-cell immune
responses peaked on day 14 and the antibody response rose by day 28.
Neutralising antibody responses against SARS-CoV-2 were detected in 91% of
participants. After a second vaccine application, called boost, this number
rose to 100%. After a booster dose, all participants had neutralising activity.
Just a friendly reminder: we should be grateful for
the existence of vaccines that have helped prevent the spread of terrible
diseases, such as tuberculosis and polio. Both brought huge suffering in
multiple countries around the world and were controlled thanks to the
implementation of vaccines!
I encourage you to check on the links below
and learn more about the different vaccines and the research behind them. Be
aware of your own cognitive bias, for example, stop citing the inexistent
connection between autism and vaccines, that research has now been thoroughly
debunked, the Lancet journal issued a retraction on Wakefield’s paper, and he
lost his medical licence.
Let me leave you with this great advice from the WHO
about how to respond to vaccine deniers:
“Vaccine-preventable diseases can be very severe,
and still cause millions of deaths per year around the world. Even with the
best available care in the world, vaccine-preventable diseases can cause
permanent disability and even death. Prevention is by far the best
intervention.”
“There are no equally safe and effective
alternatives to vaccinations.”
“The scientific evidence is clear: vaccination
is the most effective health intervention for prevention of many serious
diseases.”
“We as an institution/agency are aiming to
sustain the health of every individual member of the public. We are sorry that
you have lost trust in our effort, but we hope to regain it.”
“The scientific evidence is clear; vaccination
is a safe way to prevent many serious diseases. Any theoretical risk to the
individual and society is far outweighed by the risks to one and all of not
doing so.“
References:
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31604-4/fulltext
https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html
https://www.raps.org/news-and-articles/news-articles/2020/3/covid-19-vaccine-tracker
https://www.youtube.com/watch?v=-dYWZMx-Lfs