How long is the Pfizer COVID vaccine effective.
                     H O W  L O N G  I S  
T H E  P F I Z E R  
C O V I D  
V A C C I N E  
E F F E C T I V E ?
INTRODUCTION
• The COVID-19 vaccine for Pfizer/BioNTech is currently ongoing in many countries and has come 
to an end in clinical research. 
• In the UK, Canada and the United States, Regulatory Authorities issued approval for immediate 
or emergency use of the vaccine to the public. 
Source: ndtv.com
EFFICIENCY OF THE VACCINE
• It is now possible to create a biological barrier to the virus. An extremely efficient vaccination 
combined with existing physical hurdles increases the expectation that the pandemic will be 
prevented. 
Source: theconversation.com
SAFETY
• The safety review involved nearly 37,000 individuals. Half got a vaccine in two doses, and half 
a placebo injection in the other half. 
• Especially in people at greater risk of COVID-19 the vaccine has been tested. About 40% of 
participants over 55 years old were overweight, around a third overweight and about third 
obese. 
Source: mittechnologyreview.com
PARTICIPANTS
• The vaccine was nevertheless tested more than others in some classes. The majority of 
participants (83 per cent) were white and most (77 per cent) were conducted in the United 
States (with additional participants in Argentina, Brazil and South Africa). 
Source: theconversation.com
EFFECTIVENESS OF THE VACCINE
• More than 36,000 individuals were analysed to assess the potency of the vaccine (the 
percentage of people it protected from the disease under controlled conditions). 
• In contrast with 169 people injected with placebo, nine vaccine participants were infected with 
the virus. This leads to an effectiveness of 95 percent. Above all, the wellbeing of persons was 
high, regardless of age, race or underlying conditions of health. 
Source: news.usc.edu
DOSES
• Between the first and second doses, some participants were infected to stress that second dose 
was appropriate (efficacy after just the first dose was only 52 percent ). If you take all doses, at 
least in the short term, you are more likely to be safe against COVID-19.
Source: reuters.com
SIDE EFFECTS
• After immunisation, some participants reported side effects such as headache, exhaustion or 
discomfort at the injection site. 
• Most of these reactions were mild to severe, and within three days they resolved. After at least 
two months after the second immunisation, no more reactions were reported.
Source: theconversation.com
ALLERGIC REACTIONS 
• No less typical side-effects can be observed, for instance. This is why the vaccine needs now to be controlled 
so carefully, and the authorities need to intervene quickly if people react to it suddenly. 
• In the UK definitive intervention in the case of previously unseen side effects of someone with a long history 
of allergic reactions has also been seen. 
Source: nbcnews.com
STILL A LOT FIND OUT!
• Overall, this trial provided confidence in the vaccine’s efficacy and robustly documented its safety. However, 
this doesn’t mean the study shows what will happen in the real world. We cannot presume that the 
experiences of 19,000 vaccinated individuals will extrapolate to millions of people.
Source: theconversation.com
INTERVENTION
• Similarly, the effectiveness of the vaccine in the real world – so called its efficacy – can often be diminished 
when it is used in a larger range of individuals and for prolonged periods of time.
• And important questions still need to be addressed, particularly about the duration of the 
vaccine's safety. It is virtually inevitable that the initially generated immune response will 
decline over time. 
Source: dnaindia.com