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COVID-19 Vaccine Explained: What Is Placebo And Why Is It Used In Vaccine Trials?

According to experts, placebo-controlled trials are regarded as a standard method for testing the efficacy of new drugs. Experts explain why

COVID-19 Vaccine Explained: What Is Placebo And Why Is It Used In Vaccine Trials?
  • Placebo is a medicine designed to have no therapeutic value: Experts
  • Researchers compare results of the vaccine with those obtained from placebo
  • Aim of placebo is to see how many trial volunteers naturally get the virus

New Delhi: The COVID-19 pandemic continues to pose a burden on public health systems worldwide. To fight the outbreak that has caused death of over 24.29 lakh people across the globe, researchers have been working at a break-neck speed to rollout effective vaccines against the novel coronavirus to get the world out of this unprecedented situation. As scientists and pharmaceutical companies develop vaccines, they aim to achieve a vaccine that is effective and safe. To achieve this goal, they conduct clinical trials during which half of the volunteers participating in the trial are randomly selected and given the experimental vaccine and the other half is given a placebo vaccine. The results on efficacy and side-effects obtained from both groups are compared to see whether or not the experimental vaccine is effective. NDTV spoke with experts Dr Aviral Roy, Consultant Critical Care, Medica Superspecialty Hospital in Kolkata and Dr K K Aggarwal, President of the Confederation of Medical Association of Asia and Oceania (CMAAO) and Former President, Indian Medical Association (IMA) to learn about ‘Placebo’ and why these are used in clinical trials.

Also Read: COVID-19 Vaccine Maybe Available In Open Market By Year End: AIIMS Director

What Is A Placebo?

According to the experts, a placebo is a harmless inactive substance that looks like the medicine or the vaccine that is being tested. It can be an inert tablet like a sugar pill or inert injection made of saline solution. Dr Aggarwal explained that placebos are designed to have no therapeutic value and have been used for decades in clinical trials.

How Are Placebos Used?

When a new drug is being tested, one group (called as test group) of the people who volunteered for the trial will be given that medicine/vaccine while the other group (called as placebo group) would be offered a placebo, said Dr Roy. He added that all the other conditions related to trial are kept the same from both groups and none of the individuals in the sample is told if they have received the real drug or the placebo. This is called as ‘blinding’ and it helps removing the risk of volunteers acting differently on the basis of what they have received which may tamper the outcomes of the study.

Why Is It Used In Vaccine Trials?

Placebo is used in vaccine trials because comparing results from the two groups- test group and placebo group- suggests whether changes in the test group have resulted from the vaccines or just by chance, said Dr Roy. He added that placebo-controlled trials are regarded as a standard method for testing the efficacy of new drugs and treatments.

Dr Roy explained that many volunteers are being given a placebo during the human trials (or clinical trials) of COVID-19 vaccine candidates. He said that if actual vaccines are given to all the volunteers, the side-effect and long-term outcomes will not be known properly. He said,

True vaccine is given to the individuals who received placebo only after the tests are over and the findings are obtained. While this may feel as unethical, it should be noted that people participate in clinical trials voluntarily with altruistic motives of helping in developing a new drug, vaccine or treatment. They are made aware of the fact that they might be offered placebo at the time of signing up for the trial itself.

Also Read: Pace Of COVID-19 Vaccination Has Been Kept Slow Intentionally To Iron Out Glitches: Indian Council Of Medical Research

Placebos Are Inert But May Still Have Some Effect On The Receiver: Experts

While placebos may not have any effect on the disease, it does have a psychological effect on the receiver, said Dr Aggarwal. He explained that the receiver thinks that they have received the real vaccine or drug and because of their faith in the experimental medicine, they perceive an improvement in their condition which sometimes translate into an effect on their body as well. This is called as ‘Placebo Effect’, he said. Dr Aggarwal added,

We use placebo many times in the real treatment as well. ‘Faith’ is a significant emotion that has an effect not only on a person’s mind and actions but also on their body because the mind releases such hormones that change a person’s physical condition. While treating critical patients we often tell them in a reassuring manner that they have become better and will be discharged from the hospital soon. This is a placebo therapy only and it actually helps in speedy recovery of the patient because if they believe that they will get alright soon, half the battle is already won, because positive thoughts will increase their will power which will, in turn, have a positive impact on their body. The multi-vitamins that we subscribe to patients along with the medicine is another example of using placebo in treatments. Taking multi-vitamins helps patients build faith in their own body and immune system to fight the disease.

Also Read: COVID-19 Explained: Will The COVID-19 Vaccine Be Effective Against The Latest Coronavirus Variant?

NDTV – Dettol Banega Swasth India campaign is an extension of the five-year-old Banega Swachh India initiative helmed by Campaign Ambassador Amitabh Bachchan. It aims to spread awareness about critical health issues facing the country. In wake of the current COVID-19 pandemic, the need for WASH (WaterSanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign highlights the importance of nutrition and healthcare for women and children to prevent maternal and child mortality, fight malnutrition, stunting, wasting, anaemia and disease prevention through vaccines. Importance of programmes like Public Distribution System (PDS), Mid-day Meal Scheme, POSHAN Abhiyan and the role of Aganwadis and ASHA workers are also covered. Only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and become a Swasth or healthy India. The campaign will continue to cover issues like air pollutionwaste managementplastic banmanual scavenging and sanitation workers and menstrual hygiene


Coronavirus has spread to 196 countries. The total confirmed cases worldwide are 26,78,24,983 and 52,79,148 have died; 22,84,48,447 are active cases and 3,40,97,388 have recovered as on December 9, 2021 at 3:47 am.


3,46,66,241 9,419Cases
94,742 1,009Active
3,40,97,388 8,251Recovered
4,74,111 159Deaths
In India, there are 3,46,66,241 confirmed cases including 4,74,111 deaths. The number of active cases is 94,742 and 3,40,97,388 have recovered as on December 9, 2021 at 2:30 am.

State Details

State Cases Active Recovered Deaths

66,40,888 893

9,964 157

64,89,720 1,040

1,41,204 10


51,78,892 5,038

41,615 887

50,95,263 4,039

42,014 112


29,99,098 399

7,284 155

29,53,565 238

38,249 6

Tamil Nadu

27,32,648 703

7,946 36

26,88,142 728

36,560 11

Andhra Pradesh

20,74,217 181

2,011 3

20,57,749 176

14,457 2

Uttar Pradesh

17,10,502 10

139 7

16,87,452 3


West Bengal

16,20,803 574

7,576 0

15,93,659 568

19,568 6


14,41,514 65

404 28

14,16,010 36

25,100 1


10,50,760 255

1,931 11

10,40,403 264

8,426 2


10,07,075 37

341 9

9,93,140 27

13,594 1


9,54,984 40

236 16

9,45,792 24



8,27,873 67

417 45

8,17,361 22


Madhya Pradesh

7,93,288 14

140 1

7,82,619 13



7,71,904 29

223 15

7,61,626 14



7,26,259 9

36 6

7,14,133 3



6,77,546 205

3,871 19

6,69,673 185

4,002 1


6,18,042 134

2,541 24

6,09,374 158



6,03,578 22

350 0

5,86,614 20

16,614 2


3,49,383 16

129 7

3,44,113 23



3,44,402 17

192 3

3,36,799 14


Jammu And Kashmir

3,38,198 151

1,639 38

3,32,070 111

4,489 2

Himachal Pradesh

2,27,753 69

722 14

2,23,174 81

3,857 2


1,79,307 65

441 37

1,75,478 28



1,37,377 320

3,049 10

1,33,819 309

509 1


1,29,128 23

230 1

1,27,022 22



1,25,429 23

325 5

1,23,119 28



84,888 14

94 11

83,968 3



84,631 12

240 11

82,916 23



65,515 7

67 2

64,628 5


Arunachal Pradesh

55,298 3

29 2

54,989 5



32,390 8

200 2

31,785 6



32,143 1

116 2

31,328 3



21,749 14

230 17

21,304 31


Dadra And Nagar Haveli


0 0





11 0



Andaman And Nicobar Islands

7,691 1

3 0

7,559 1


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