The new phase of centralized free COVID-19 vaccination has begun from June 21st, and in a historic feat, 80,95,314 doses were provided on the first day of the new phase of COVID-19 vaccination. This is the world's largest single-day number of jabs. However, having a suitable and effective vaccine is just as crucial as having the free vaccines.
Which vaccine against Covid-19 is the most effective? For the
past two and a half months, this has been the most frequently asked question
about Covid-19. To be honest, finding a correct and legitimate response to this
has been pretty difficult. In this episode, we'll attempt to solve this complex
and challenging question. Let me request my viewers to watch this video patiently
till the end. We'll use the prestigious medical journal “The Lancet" to
discuss the efficacy of the several Covid-19 vaccines available in the market.
Before we go into the specifics of vaccine efficacy, let's have
a quick look at the current immunisation status of the developed countries.
Perhaps, that will help us to understand the issue in a better way.
To begin, let’s have a look at how the US vaccine rollout
looks right now. According to the TIME, USA, around 44% of Americans have
received both doses of the Two-shot Pfizer and Moderna drugs or a single
injection of the one-dose Johnson&Johnson version of vaccine. Please note
that the US has entered into the sixth month of its Covid-19 vaccine rollout.
If you consider to add on the population those who have received only the first
dose of Pfizer or Moderna – the total figure stands at just 50%.
On 29th April, the Cable News Network (CNN)
reported that the vaccine manufacturing companies changed shipment sizes as
coronavirus vaccine demands declined. What does this actually mean? The
statement of Freeman would perhaps clarify this. Lori Tremmel Freeman, CEO of
County and City Health Officials told CNN, “Many of our health departments,
especially those in rural America, are providing feedback that they either need
smaller dosage vials or we will have to contend with waste.” This statement of
Freeman came in the background of a CNN poll conducted by SSRS which states
that at least 25% Americans say that they will not get the shot of vaccine.
Because
of the widespread public opposition, state and municipal officials in the
United States of America have asked vaccine makers to reduce the size of
vaccination vials. As a result, Pfizer announced that it would offer lower
package sizes. The shipment size was lowered from a pack containing 1,170 doses
to a pack containing just 450 doses. The Executive Director of the Association
of Immunization Managers, on the other hand, believes that a push should be
made to change vaccination practises. Gradually, we've come across a few
different forms of such push!
Free
beer and marijuana are being offered by the US government in exchange for
Covid-19 vaccine. The state's liquor and cannabis board recently stated that
state-licensed cannabis businesses will be able to provide adults with
"free joints" after their first or second immunisation at
participating outlets. Across the United States, health authorities and a
number of private organisations are implementing such efforts, which are aimed
mostly at the younger generation. The viewers of this channel must decide
whether or not it is justified to give out free beer and marijuana to young
people in order to advertise the Covid-19 vaccine. In any case, while Indians
have been queuing since midnight and fighting one other over a Covid jab, the
United States of America is attempting to entice its countrymen to do the same.
Let's
have a look at the situation of cumulative vaccine uptake in European Union
(EU) and European Economic Area (EEA) countries (EEA). As of June 17th, 2021,
less than 30% of adults in European countries have been fully vaccinated
against Covid-19, with roughly 54% receiving only a single dose of the vaccine.
There is a bold assertion that some indicators of reduced Covid-19 transmission
can be found in Europe as a result of immunisation programmes across the
continent. But, to what extent is this true? Let's take a look at some of the
countries' immunisation data.
Bulgaria
and Finland, for example, had completed immunisation for roughly 10% of their
population as of May 30, 2021. Around 18 percent in Sweden, 20 percent in
Austria, Norway, and France, and 21 to 23 percent in the Netherlands, Germany,
Belgium, Portugal, Italy, and Spain. Almost all European countries are in a
similar situation. Malta is the only European country with a vaccination rate
of around 49 percent. Hungary is next, with roughly 47% of its vaccinations
completed.
But
what are the likely causes of Europe's immunisation program's dismal results?
Viewers will notice that vaccine dose availability was never an issue. Take
Finland as an example. The producers provided around 76 Covid-19 vaccination
doses for every 100 people in Finland. However, only about 11 people out of
every 100 in Finland have received the Covid vaccine. Take a look at the chart,
which shows the immunisation status of some of Europe's most advanced
countries.
|
Sl No. |
Name of the country |
|
Vaccinated |
Availability |
|
|
|
|
(per 100 |
(per 100 |
|
|
(Status up to 30 May, 2020) |
|
population) |
population) |
|
1 |
Bulgaria |
|
9.70 |
55.20 |
|
2 |
Finland |
|
10.90 |
75.80 |
|
3 |
Sweden |
|
18.20 |
79.90 |
|
4 |
Austria |
|
20.70 |
70.00 |
|
5 |
Norway |
|
20.70 |
76.90 |
|
|
|
|
|
|
|
Sl No. |
Name of the country |
|
Vaccinated |
Availability |
|
|
|
|
(per 100 |
(per 100 |
|
|
|
|
population) |
population) |
|
6 |
France |
|
20.90 |
76.40 |
|
7 |
Netherlands |
|
21.00 |
81.30 |
|
8 |
Germany |
|
21.10 |
79.90 |
|
9 |
Belgium |
|
22.90 |
75.90 |
|
10 |
Portugal |
|
23.10 |
75.90 |
|
|
|
|
|
|
|
Sl No. |
Name of the country |
|
Vaccinated |
Availability |
|
|
|
|
(per 100 |
(per 100 |
|
|
|
|
population) |
population) |
|
11 |
Italy |
|
23.50 |
75.10 |
|
12 |
Spain |
|
23.60 |
71.90 |
|
13 |
Hungary |
|
44.70 |
166.70 |
It
is quite clear that despite substantial vaccine supply, the vaccination push in
some of Europe's most sophisticated countries has yet to achieve sufficient
success.
When
we look at Australia and Japan, the scenario for vaccine proponents is much
less favourable. As of June 17th, 2021, only approximately 3% of Australians
had had a full vaccination, while about 21% had received only one dosage. As of
June 17th, little over 6% of people in Japan had been fully vaccinated, while
roughly 16% had just received one dosage.
The
poor performance of many affluent countries when it comes to Covid-19
vaccination raises concerns about the vaccines' efficacy. Regarding the FDA
approval of Covid-19 vaccinations, viewers should be aware that “Currently, no
coronavirus vaccine is fully approved by the FDA. All the vaccines were given
emergency use authorization only.
FDA
approval of a drug, which requires a rigorous and structured process, means
that data on the drug’s effects have been reviewed by the Centre for Drug
Evaluation and Research which rules on whether the drug’s benefits outweigh its
known and potential risks. The fact that none of the Covid-19 vaccines have
received FDA clearance, demonstrates that the efficacy of such candidate
vaccines could not overcome their potential dangers. That is likely the most
important factor for individuals lack of interest in the Covid-19 vaccination in
developed countries.
With
this background in mind, now, we'll use Lancet to discuss the efficacy of
Covid-19 vaccines. The study that we will discuss was published in Lancet
Microbe on April 10th of this year.
At
present, approximately 96 COVID-19 vaccines are at various stages of clinical
development and we have the interim results of four vaccines which were
published in scientific journals. These vaccines are – the Pfizer–BioNTech
vaccine, the Moderna vaccine, the AstraZeneca– Oxford vaccine and the Gamaleya
[Sputnik V] vaccine. We also have three studies through the US Food and Drug
Administration (USFDA) briefing documents on the Pfizer–BioNTech, Moderna and
Johnson & Johnson vaccines. Excerpts of these results have been widely
communicated and debated through press releases and media, more than the scientific
community and thus sometimes in misleading ways. Attention has focused on
vaccine efficacy by comparing the reduction of the number of symptomatic cases.
However, understanding the efficacy and effectiveness of vaccines in totality is
less straightforward than it might seem.
Vaccine
efficacy is generally reported as a relative risk reduction (RRR). What is
relative risk reduction? Relative risk reduction is how much risk is reduced in
an experimental group compared to a control group. For example, we have two
groups of people. One group has been vaccinated (which is termed as
experimental group) and the other group has not been vaccinated (and, is termed
as control group). Let’s say, in the control group, those who were not
vaccinated, 20% people died of Covid-19 and in the experimental group 5% people
died of Covid-19. 20% is called as control group event rate (CER) and 5% is
called as experimental group event rate (EER).
The
formula to derive the relative risk reduction is:
RRR
= (CER-EER)/CER
= (0.20-0.05)/0.05
= (0.15)/0.05
= 0.3
= 30%
In
other words, the death rate in the vaccinated group is 30% less. Although
relative risk reduction provides some information about risk, but it does not
say anything about the actual odds of what is happening. RRR considers only
participants which varies between populations and over time. Therefore, when
you see a headline in the media like relative risk reductions of 95% for the
Pfizer–BioNTech, 94% for the Moderna, 90% for the Sputnik V, 67% for the Johnson
&Johnson, and 67% for the AstraZeneca–Oxford vaccines, the report is
usually referring to relative risk which is half-truth. This leaves us with the
unanswered question as to whether a vaccine with a given efficacy in the study
population will have the same efficacy in another population with different
levels of background risk of COVID-19. But this is an important question
because transmission intensity varies between countries, affected by factors
such as public health interventions and virus variants.
To
derive an estimate of vaccine effectiveness, the absolute risk reduction (ARR)
has to be calculated. Absolute risk reduction which is also called as risk
difference is the absolute difference between the control group and the
experimental group. While the relative risk reduction considers only the participants
of the trial who could benefit from the vaccine, the absolute risk reduction
(ARR), considers the whole population in terms of the difference between attack
rates with and without a vaccine. Subtracting the Experimental Event Rate from
the Control Event Rate yields the absolute risk reduction. If we take the
previous example of relative risk reduction, the absolute risk reduction will
be:
CER-EER
= 0.20 – 0.05 = 0.15 = 15%
When
computing the absolute risk reduction, the relative risk reduction of 30% was
reduced to only 15%.
According
to the Lancet Microbe study, absolute risk reductions are often overlooked,
because they have a significantly smaller effect size than relative risk
reductions. To understand this, let’s have a look at this chart:
|
Name
of the Vaccine |
Relative
Risk Reduction (RRR) |
Absolute
Risk Reduction (ARR) |
|
AstraZeneca–Oxford |
67% |
1.3% |
|
Moderna |
94% |
1.2% |
|
Johnson
& Johnson |
67% |
1.2% |
|
Gamaleya (Sputnik V) |
90% |
0.93% |
|
Pfizer–BioNTech |
95% |
0.84% |
With
the use of only Relative Risk Reductions, and omitting Absolute Risk Reductions,
the reporting bias has been introduced by the vaccine manufacturers, which
affected the interpretation of vaccine efficacy. When communicating about
vaccine efficacy, a full picture of what the data actually show is important. Comparisons
should be based on the combined evidence that puts vaccine trial results in
context and not just looking at one summary measure. Ranking the vaccines by their
reported efficacies based only on the relative risk reductions is unfair. These
studies that measured the efficacy and effectiveness of vaccines are based on the
prevention of mild to moderate COVID-19 infection; they were not designed to
conclude on prevention of hospitalisation, severe disease, or death, or on
prevention of infection and transmission potential. Assessing the suitability
of vaccines must consider all indicators, involving safety, deployability,
availability, and costs.
Unfortunately, the vaccines that are currently available on the market do not meet these critical requirements. Therefore, we will have to wait for the right vaccine to arrive to combat Covid-19.
