The efficacy, effectiveness and efficiency of Covid-19 vaccine: An ‘Evidence-based’ view

WHO vaccines with emergency approval with the relevant web links to the WHO site

Sinovac – 1 June 2021

WHO today validated the Sinovac-CoronaVac COVID-19 vaccine for emergency use, giving countries, funders, procuring agencies and communities the assurance that it meets international standards for safety, efficacy and manufacturing. The vaccine is produced by the Beijing-based pharmaceutical company Sinovac. Link

Sinopharm – 7 May 2021

WHO today listed the Sinopharm COVID-19 vaccine for emergency use, giving the green light for this vaccine to be rolled out globally. The Sinopharm vaccine is produced by Beijing Bio-Institute of Biological Products Co Ltd, subsidiary of China National Biotec Group (CNBG). LINK

Moderna – 30 April 2021

Today, WHO listed the Moderna COVID-19 vaccine (mRNA 1273) for emergency use, making it the fifth vaccine to receive emergency validation from WHO.

WHO’s Emergency Use Listing (EUL) assesses the quality, safety and efficacy of COVID-19 vaccines and is a prerequisite for COVAX Facility vaccine supply. It also allows countries to expedite their own regulatory approval to import and administer COVID-19 vaccines.

Jansen – 12 March 2021

The World Health Organization (WHO) today listed the COVID-19 vaccine Ad26.COV2.S, developed by Janssen (Johnson & Johnson), for emergency use in all countries and for COVAX roll-out. The decision comes on the back of the European Medicines Agency (EMA) authorization, which was announced yesterday.

AstraZeneca – 15 Febuary 2021

Pfizer/BioNTech – 31 December 2020

 The World Health Organization (WHO) today listed the Comirnaty COVID-19 mRNA vaccine for emergency use, making the Pfizer/BioNTech vaccine the first to receive emergency validation from WHO since the outbreak began a year ago.


This is the comparison made by UpToDate of the vaccines used in the USA approved by the FDA

COVID-19 vaccine characteristics – UpToDate One PAge


  1. None of the vaccines have been studied head-to-head, and thus comparative efficacy is uncertain.
  2. Differences in the magnitudes of effect reported from phase III trials could be related to factors other than efficacy, including differences in the trial populations and locations, timing of the trials during the pandemic, and study design.
  3. Most efficacy estimates were determined with a median follow-up of two months after vaccination.
  4. There is no information regarding the Sinopharm vaccine on this comparison although it is also approved under emergency authorisation.
  5. UpToDate is a US product and in this era it is difficult to be unbiased when the stakes are huge in financial profits in the worlds leading business of vaccine production.


‘Efficacy, Effectiveness and Efficiency’ – the meaning really matters!         

Australian Prescriber 2000;23:114-5, 1 June 2000

How is it, that guidelines for treatment often seem unrelated to the patient sitting in front of the doctor?

Guidelines are mostly based on evidence gathered from randomised controlled trials. These trials are very good at assessing efficacy – that is, can a treatment work?

Despite this, trials are not without substantial biases. Many people may be screened before a few are chosen to be included in a study, yet the results of the study will be applied to the very people who were excluded. The population studied in trials tends to be young, male, white, suffering from a single condition and using a single treatment. Most patients, at least in general practice, do not fit this description. They often have multiple illnesses, take multiple medications and are either too young or too old to have been included in clinical trials.

Efficacy is defined in relation to medications as the extent to which a drug has the ability to bring about its intended effect under ideal circumstances, such as in a randomised clinical trial

Efficacy is not the same as effectiveness. A treatment is effective if it works in real life in non-ideal circumstances. In real life, medications will be used in doses and frequencies never studied and in patient groups never assessed in the trials. Drugs will be used in combination with other medications that have not been tested for interactions, 

Effectiveness can be defined as the extent to which a drug achieves its intended effect in the usual clinical setting’.1 It can be evaluated through observational studies of real practice. This allows practice to be assessed in qualitative as well as quantitative terms

It is an irony that drugs are licensed for use almost exclusively on the results of controlled trials, yet they are withdrawn from use because of observational data that would not be acceptable to licensing authorities. Biases are present in observational studies, just as they are in trials, but they can be defined and often controlled for, giving these studies a much greater value than that currently awarded to them.

Efficiency depends on whether a drug is worth its cost to individuals or society. The most efficacious treatment, based on the best evidence, may not be the most cost-effective option. It may not be acceptable to patients. 

China has administered more than 1 billion Covid-19 vaccine doses, an astonishing milestone that comes as the country rolls out an unrivaled inoculation drive.

A total of 1,010,489,000 doses have been given as of Saturday, China’s National Health Commission (NHC) said in a statement. Those doses are almost 40% of the 2.5 billion shots administered globally.
 The NHC said 100 million doses were given in the five days up to and including Saturday, according to state media outlet Xinhua.
The 1 billion number is all the more remarkable given that China’s rollout had a stuttering start.
China only reached its first million administered doses on March 27 — two weeks behind the US. But the pace picked up significantly in May, with more than 500 million shots given over the past month, according to data from the NHC.
“It took China 25 days to climb from 100 million doses to 200 million doses, 16 days to increase from 200 million to 300 million, and six days from 800 million to 900 million,” Xinhua reported.