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doi: 10.12032/IDR2021B0207001
Infectious Diseases Research 2021, 2(1), 5
COMMENT
Covid-19 vaccines and Community Immunity
Bhoj R SinghBhoj R Singh11**,,Sumedha GandharavaSumedha Gandharava22,,Richa GandharvaRicha Gandharva33
1Division of Epidemiology, ICAR-Indian veterinary Research Institute, Izatnagar, India; 2Boise State University, Boise, ID,
USA; 3University College London, London, UK.
**Corresponding toCorresponding to:: 438 MLB, Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Izatnagar, India-243 122,
E-mail: brs1762@gmail.com
Infectious Diseases Research
Infectious Diseases Research 2021, 2, 5
doi: 10.12032/IDR2021B0207001
of 7
COMMENT
Abstract
This short review analyzed the present status of different Covid-19 vaccine, their utility in Covid-19 control and as
a tool of herd or community immunity. Most of the vaccines approved to date have insufficient data to predict their
protective potential against COVID-19 virus infection and carriage (potential as silent spreader). We also not know
the period of protective immunity and their ability to protect against variants of viruses emerging fast. The vaccine
at the most can be used as personal protective shots against COVID-19.
After global approval of one or more Covid-19
vaccines, Covid-19 has become the 28th vaccine
preventable human disease [1]. Not all infectious
diseases can be presently fought with a vaccine. The
HIV, respiratory syncytial virus, and the cancer-
causing Epstein-Barr virus kill millions of people
every year and have no vaccine yet. Moreover, not
everyone is fortunate enough to be vaccinated due to
several economic, social, ethical, geographical and
health reasons leading to vaccine preventable deaths.
The health reasons for avoiding vaccines include
1) historical evidences of severe or life-threatening
reaction to the vaccine (allergies), 2) infants younger
than 6 months old (for many vaccines), 3) ongoing
moderate or severe illness and 4) people with chronic
wasting diseases or those with Guillain-Barre syndrome
(characterized by difficulties with eye muscles and
vision, swallowing, speaking, chewing, lack of sensations
in the hands and feet but severe pain especially at
night, problems of coordination and steadiness beside
arrhythmic heart beat and disturbed blood pressure).
The most common flu shots are not suggested be
administered to children under 2 years of age, or
young children with a history of asthma or wheezing,
children or adolescents on long-term aspirin treatment
and pregnant women. Also, people with chronic
diseases, (such as heart disease, liver disease, or
asthma), people with certain muscle or nerve diseases
(that can cause breathing problems) and people who
have (or are living with family members) compromised
immune systems should not go for flu vaccine. The
vaccine shots usually fail to protect elderly from
common flu. However, we have yet to learn a lot about
Covid-19 vaccine suitability, which may be learnt after
several complications yet to be reported after mass
scale Covid-19 vaccination.
Types of Vaccines
Preventive and therapeutic are two groups of
vaccines, a vaccine can belong to both of the groups
depending upon the way it is designed. Vaccines are
primarily used for prevention of the diseases and
disease outbreaks aiming to disease control and
eradication. Therapeutic vaccines are used mostly for
diseases with a long course or slow progression but
usually of high fatality like rabies, cancers (antigen
vaccine), dendritic cell vaccine (still under research),
autologous and allogeneic vaccine (for certain tumors).
Some therapeutic vaccines for HIV and Alzheimer's
disease are in experimental stage with promising
outcome[2].
Covid-19 vaccines:
We are still in infancy to understand the effect
and outcome of Covid-19 vaccines and vaccination in
its entirety; we neither know their therapeutic value
nor the disease prevention potential in detail.
Types of Covid-19 Vaccines:
The potential vaccines for COVID-19 either
approved for use or in trial stage include:
·Ina cti vated o r wea kened viru s vaccines : the
inactivated or weakened virus is incapable of
causing disease, but induces a protective immune
response (CoVaxin from Bharat Biotech with
claimed 70.4 percent efficacy, India, Sinovac
Biotech vaccine from China with more than 50
percent efficacy).
·Protein-based vaccines: subcomponent vaccines
contain harmless fragments of the virus like
spike proteins or protein shells that mimic the
COVID-19 virus i. e., ghost viruses or virus like
particles (VLPs) are often safe and generate an
immune response (EpivacCorona vaccine from
Russia).
·Viral vector vaccines: use a harmless career virus
either natural or genetically engineered designed
to carry genes to produces Corona-virus proteins
in host to generate an immune response (Gam-
Covid-Vac or Sputnik V from Russia with 92
percent efficacy, AstraZeneca Oxford Covisheild
with claimed 90 percent efficacy, both used
Adenovirus as vector for Covid-19 spike
proteins)
·RNA and DNA vaccines: a cutting-edge approach
that uses genetically engineered mRNA or DNA
to generate a protein, often requiring a potent
delivery system and adjuvant to induce the
immune system to mount a protective response.
[Moderna (mRNA 1273) and Pfizer (BNT162b2 )
vaccines, with 94-95 percent efficacy].
Will other vaccines help protect me from
COVID-19?
Scientists have claimed and are studying whether
some existing vaccines–such as the Bacille Calmette-
Guérin (BCG) vaccine, which is used to prevent
tuberculosis–are also effective for COVID-19. However,
the protection conferred by BCG vaccine is non-
specific [3].
Acknowledgement:
We thank to all those who are worried about Covid-19 and its vaccines.
Competing interests:
None.
Citation:
Singh B R, Gandharava S, Gandharva R. Covid-19 vaccines and Community Immunity. Infectious Diseases
Research 2021, 2 (1): 5.
Executive Editor: Yong-Di Xing
Submitted: 7 February 2020, Accepted: 20 February 2020, Online: 22 February 2021
2
Infectious Diseases Research 2021, 2, 5
doi: 10.12032/IDR2021B0207001
of 7
COMMENT
After global approval of one or more Covid-19
vaccines, Covid-19 has become the 28th vaccine
preventable human disease [1]. Not all infectious
diseases can be presently fought with a vaccine. The
HIV, respiratory syncytial virus, and the cancer-
causing Epstein-Barr virus kill millions of people
every year and have no vaccine yet. Moreover, not
everyone is fortunate enough to be vaccinated due to
several economic, social, ethical, geographical and
health reasons leading to vaccine preventable deaths.
The health reasons for avoiding vaccines include
1) historical evidences of severe or life-threatening
reaction to the vaccine (allergies), 2) infants younger
than 6 months old (for many vaccines), 3) ongoing
moderate or severe illness and 4) people with chronic
wasting diseases or those with Guillain-Barre syndrome
(characterized by difficulties with eye muscles and
vision, swallowing, speaking, chewing, lack of sensations
in the hands and feet but severe pain especially at
night, problems of coordination and steadiness beside
arrhythmic heart beat and disturbed blood pressure).
The most common flu shots are not suggested be
administered to children under 2 years of age, or
young children with a history of asthma or wheezing,
children or adolescents on long-term aspirin treatment
and pregnant women. Also, people with chronic
diseases, (such as heart disease, liver disease, or
asthma), people with certain muscle or nerve diseases
(that can cause breathing problems) and people who
have (or are living with family members) compromised
immune systems should not go for flu vaccine. The
vaccine shots usually fail to protect elderly from
common flu. However, we have yet to learn a lot about
Covid-19 vaccine suitability, which may be learnt after
several complications yet to be reported after mass
scale Covid-19 vaccination.
Types of Vaccines
Preventive and therapeutic are two groups of
vaccines, a vaccine can belong to both of the groups
depending upon the way it is designed. Vaccines are
primarily used for prevention of the diseases and
disease outbreaks aiming to disease control and
eradication. Therapeutic vaccines are used mostly for
diseases with a long course or slow progression but
usually of high fatality like rabies, cancers (antigen
vaccine), dendritic cell vaccine (still under research),
autologous and allogeneic vaccine (for certain tumors).
Some therapeutic vaccines for HIV and Alzheimer's
disease are in experimental stage with promising
outcome[2].
Covid-19 vaccines:
We are still in infancy to understand the effect
and outcome of Covid-19 vaccines and vaccination in
its entirety; we neither know their therapeutic value
nor the disease prevention potential in detail.
Types of Covid-19 Vaccines:
The potential vaccines for COVID-19 either
approved for use or in trial stage include:
·Ina cti vated o r wea kened viru s vaccines : the
inactivated or weakened virus is incapable of
causing disease, but induces a protective immune
response (CoVaxin from Bharat Biotech with
claimed 70.4 percent efficacy, India, Sinovac
Biotech vaccine from China with more than 50
percent efficacy).
·Protein-based vaccines: subcomponent vaccines
contain harmless fragments of the virus like
spike proteins or protein shells that mimic the
COVID-19 virus i. e., ghost viruses or virus like
particles (VLPs) are often safe and generate an
immune response (EpivacCorona vaccine from
Russia).
·Viral vector vaccines: use a harmless career virus
either natural or genetically engineered designed
to carry genes to produces Corona-virus proteins
in host to generate an immune response (Gam-
Covid-Vac or Sputnik V from Russia with 92
percent efficacy, AstraZeneca Oxford Covisheild
with claimed 90 percent efficacy, both used
Adenovirus as vector for Covid-19 spike
proteins)
·RNA and DNA vaccines: a cutting-edge approach
that uses genetically engineered mRNA or DNA
to generate a protein, often requiring a potent
delivery system and adjuvant to induce the
immune system to mount a protective response.
[Moderna (mRNA 1273) and Pfizer (BNT162b2 )
vaccines, with 94-95 percent efficacy].
Will other vaccines help protect me from
COVID-19?
Scientists have claimed and are studying whether
some existing vaccines–such as the Bacille Calmette-
Guérin (BCG) vaccine, which is used to prevent
tuberculosis–are also effective for COVID-19. However,
the protection conferred by BCG vaccine is non-
specific [3].
3
Infectious Diseases Research 2021, 2, 5
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COMMENT
Will COVID-19 vaccines provide long-term
protection?
It's too early to know and claim if COVID-19
vaccines will either provide long-term protection or
not but at present it is claimed to protect for 6 ‒8
months after a booster vaccination. This is an
assumption and based on the available data suggesting
that most of those people who recover from COVID-
19 develop a protective antibody titres (based on
which serum therapy has been practiced in many
nations using convalescent serum) and cellular
immune response which provides protection from re-
infection for 6‒8 months.[4]
Who should not get Covid-19 vaccine? [5]
WHO has advised people that those with some
medical conditions should not get certain Covid-19
vaccines, or should wait before getting vaccine. Such
warning conditions are chronic illnesses or treatments
(like chemotherapy) that affect the immune system;
severe and life-threatening allergies to vaccine
ingredients, which are very rare; or those with severe
illness and a high fever on the day of vaccination.
Expected side effects from vaccines?
Like any other medicine, vaccines are known to
cause several mild side effects; similarly, Covid-19
vaccines may also induce low-grade fever, or pain or
redness at the injection site. Most of the mild reactions
go away within a day or a few days on their own.
Severe or long-lasting side effects are extremely rare.
Vaccines are continually monitored for safety, to detect
rare adverse events.
Reported Side effects of Covid-19 vaccines during
their trials and a short history of their use:
Participants of several Covid-19 vaccine trials
have experienced mild, lingering, and in some cases,
'totally strange' side-effects.
It is said that if you have decided to get Covid-19
vaccine you are certain to get pain and swelling at the
site of vaccine shot (for one or more days) and fever,
chills, muscle pain, tiredness, and headache (for a day
or two) as many people get after having Flu shot
(influenza vaccine). You may need medical care if the
redness or tenderness at the site of the shot increases
after 24 hours or other side effects are worrying you or
do not seem to be going away after a few days. Side
effects may feel like flu and even affect your ability to
do daily activities, but they should go away in a few
days.[6].
Moderna trials detailed suffering from bone-
breaking chills, and a fever that went up to 102 degrees
Fahrenheit within hours of vaccine is inoculated. Onset
of production of antibodies may also cause a low-
grade or high fever, accompanied by redness and
swelling at injection site. [7].
Commonly reported side effects of the Pfizer-
BioNTech COVID-19 vaccine include fatigue (63%),
headache (55%), and muscle pain (38%). These side
effects go in a day or two. However, the most
commonly reported (by 84%) side effect from the
vaccine is an injection site reaction. It can be a little
tender; it can hurt to move the arm a little bit. Some
participants in trials reported chills, joint pain, or fever
following vaccination. Reactions were more often
reported following the second (booster) dose of the
vaccine. Serious side effects as Bell's palsy
(characterized by rapid onset of mild weakness to total
paralysis on one side of your face (facial hemiplegia,
the 7th nerve inflammation) within hours to days of
vaccination leading to facial droop and difficulty in
making facial expressions, such as closing your eye or
smiling, drooling and pain around the jaw or in or
behind your ear on the affected side) have been
reported in 0.5% of the vaccine trial participants
besides rare severe allergic reactions to vaccines can
also happen. [8].
Anaphylaxis, a potentially life-threatening allergic
reaction, has been linked in the past to multiple types
of vaccines. Severe allergic reaction after receiving the
Moderna and Pfizer vaccines (1.31 per million doses)
alerted authorities to closely see whether anaphylaxis
is linked to all Covid-19 vaccines, or merely those like
the Pfizer and Moderna vaccines made of messenger
RNA. Eight people in the Pfizer and Moderna trials
had Bell's palsy after receiving the vaccine. Having
Guillain Barré syndrome is another possibility after
getting vaccine shots. [9]. It is advised that if you have
an immediate allergic reaction after getting the first
dose of an mRNA COVID-19 vaccine, you should not
get the second dose. However, if you are allergic to
items such as food, pet, venom, environmental
allergens, or latex allergies, you should get vaccinated.
[10]. The allergic reactions after vaccine shots as per
scientific investigation may be due to the compound
polyethylene glycol (PEG), which is part of the fatty
envelope that surrounds the mRNA, the main
ingredient in the vaccine. [11].
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COMMENT
Efficacy of Covid-19 vaccines:
The Center for Disease Control and Prevention
(CDC) pointed out, "We don't know what happens
after a single dose, " William Moss (director of the
International Vaccine Access Center) says. "Certainly
we can't expect [that one dose will confer] the high
degree of protection" that both doses demonstrated in
phase 3 clinical trials. (Pfizer's vaccine, for example,
was found to be about 52 percent effective after the
first dose; effectiveness jumped to 95 percent after the
second.). An interesting finding from the Pfizer-
BioNTech and Moderna clinical trials is that while the
vaccines seem to be just as effective in older adult
participants, people 65 and older experienced fewer
side effects than younger people [12]. However, the
efficacy of Covid-19 vaccine is far better than the
effectiveness of the annual flu shot (40%).
Why Covid-19 vaccination?
The target of vaccination is to build up "community
immunity, " or herd immunity, where enough of the
population is protected from the virus and as a result
transmission slows down significantly to kill the
disease. However, vaccinologists are not sure about the
magic number (fraction of immune population) to
obtain effective herd immunity for COVID-19, they
estimated it's somewhere around 70 percent of the
population, which could take months (in nations with
developed health system) to years to achieve the target
through vaccination. This is certain that it is a very
conservative estimate and is certain to change depending
on the contagiousness of the present Covid-19 and
future mutant viruses destined to emerge at the face of
vaccination [13]. Moreover, people in reproductive age
planning to have baby in next three years are advised
to abstain from Covid-19 especially mRNA based
vaccine due to probable fear of unwanted mutations in
germ cells (not discussed openly as it may further
reduce the acceptability of the vaccines).
Natural immunity after Covid-19 infection:
People after COVID-19 infection (those had
minor ailment after infection or remained even
asymptomatic) develop fairly good and long-lasting
immune responses. Covid-19 antibodies lasted at a
good level even after 6-8 months of infection. Thus it
is envisaged that long-lasting antibody levels and
immune memory cells could potentially lessen the
severity of a re-infection [14]. The immunity after the
first infection leads to floating of an idea for an
"immunity passport" or "risk-free certificate" that
would enable individuals to travel or to return to work
assuming that they are protected against re-infection.
However, the availability of limited data evidences
questions the possibility of any such immunity passport.
Till today, no country permits a person to travel
internationally with good antibody titre report but
requires an RT-PCR based antigen detection test report.
The new vaccines were 90% and 94.5% effective,
Paul said, but "naturally acquired" COVID-19 immunity
was even better, at 99.9982% efficacy [15]. However,
a natural infection may not be the choice for getting
immune because many of those (one in three) people
who recover from Covid-19 have chronic complaints,
including exhaustion and a racing heart, for months
afterwards including people under 35 years of age with
no previous health conditions. Several of the survivors
of Covid-19 have reported symptoms similar to those
of lupus and rheumatoid arthritis. Covid vaccines, in
contrast, carry only a few and a little known risk. So
far Covid-19 vaccines have been tested in tens of
thousands of people and used in a million of people
with no serious side effects. "Once you start vaccinating
millions, you might find very, very rare events, Dr.
Hanage said. "But we have to know that they are very,
very rare, much more rare than the adverse events
associated with natural infection" of Covid-19 [16].
Another worry is "Leaky" vaccination. When a
vaccinated host keeps on shedding disease germs due
to persistence of disease causing agent without any
apparent clinical disease, it is called leaky vaccination.
Studies on Covid-19 vaccines at present are silent over
this point. Many veterinary and human vaccines are
classified as leaky because they only stop the clinical
occurrence of disease but do not protect vaccinated
person from getting infected or being carrier or disease
disseminator. The leakiness is of concern because it
increases vaccination coverage required to prevent
disease spread and can also promote the evolution of
the pathogen with increased virulence.
Do we need to practice social distancing and use
face mask even after vaccination? The answer from all
the authorities is yes though users expect it to be no.
The big questions:
Till date global infectivity (infected out of
exposed) of Covid-19 (in case of Covid-19 misclassified
as morbidity) is about 1.1 percent (0.09 percent in
BCG using and 3.36 percent in non-BCG using
so-called developed countries) with a case fatality of
less than 3 percent i. e., overall annual mortality rate
for Covid-19 is only 0.03 percent (with masks and
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COMMENT
other preventive measures). On the other hand,
common flu having case fatality of 0.1 percent in USA
kills about 0.65 million people globally. In the last one
year Covid-19 has claimed about 1.84 million people
[17]. High mortality is common with any new strain of
flu virus as it was seen with several influenza virus
strains in past. Even minor changes may be harsh
leading to an increase in morbidity and mortality as
was seen in 2017-18 [18].
People often say that none of the Covid-19
vaccines cleared for use has immunity induction (not
yet proved the protection at face of the real infection
challenge) in more than 95 percent people (varying
from >50 to less than 95 percent) that is, only five out
of 100 may have the disease while the past one year
experience revealed that in absence of any vaccine
globally only 1.1 percent people got an infection
(varying from 0.0 to about 10 percent) and only a
fraction of those (less than five percent) contracted the
clinical infection. So how, the vaccination is superior
over no-vaccination when 5% of vaccinated and only
1.1% of non-vaccinated people are prone to get
infected by Covid-19? The 1.1% rate of contracting
infection was with all preventive measures taken, but
you have to practice all those precaution even after
vaccination, that is no relief from mask and social
distancing even after vaccination.
Further, the question is of infectivity of Covid-19
in poor or developing nations infested with tuberculosis
and using BCG vaccine is only 0.09% then why India
(where Covid-19 infectivity is just 0.7 percent) is so
much behind in the vaccination campaign? It is
surprising that in India for the disease with no vaccine
(Covid-19), causing death of less than 0.15 million and
about 10 million cases in the year 2020 there is so
much hue and cry at all the levels of governance,
enforced economically devastating lockdown; why not
so much has been done for the other more lethal but
preventable diseases as tuberculosis killing more than
0.5 million people and having 8.5 million TB patients
at any given time, diarrhoea killing 8.6 million and
malaria with 15 million cases every year in the
country [19]?
Despite all cons it is believed that vaccination
will certainly help in building up of herd immunity,
nobody knows in how much time. To have theoretically
effective herd immunity (70 percent) with the best
vaccine with 95 and 90 percent efficacy minimum
74 and 80 percent population, respectively need to be
vaccinated at least twice in a year/ biannually. Is it
possible by any means for even the most developed
nations to achieve this target every six month? If not,
then why to advocate the Covid-19 vaccine for
building community or herd immunity? It can at the
best be used as the flu shot, only available for rich and
mighty. None of the government is in position to run
such an expensive vaccination program for three years
required for getting rid of the pandemic or epidemic
state of the disease. The vaccines with less than 80
percent efficacy (Covaxin of Bharat Biotech, and
Chinese vaccine) may never be used with the aim of
inducing herd immunity to control Covid-19 epidemic/
pandemic. At the most vaccines with less than 80
percent efficacy can be used for partial personal
protection similar to use of Flu-shots against common
flu.
References
1. World Health Organization. https://www. who. int/
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202005).pdf .Accessed February 22, 2021
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2021 by the authors. Licensee TMR, Auckland，New Zealand. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution (CC
BY) license (http://creativecommons.org/licenses/by/4.0/)
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