What are the VACCINES? And how do they work?

A vaccine is composed of pathogens, that are micro-germs (microbes viruses, or bacteria) in a dead (inactive) or weak (attenuated) form or their components/genetic material that, upon entering the body of the patient aid in the production of the immune system against this infection without suffering.

The immune system of our body can detect specific components of these pathogens, referred to as ‘ antigens’, and then in response, produce ‘ antibodies’ and activate immune cells that have memory, which destroy the pathogens. It is the body’s defense system that requires an extended period of time during the process of recognizing activation, activation, and the initiation of a particular adaptive immune system. Within this time the microbe that is invading is able to rapidly multiply and overwhelm our immune system creating symptoms and damage. If you’ve been vaccinated, your body’s immunity will be in full force to combat the actual organism that is exposed, thus preventing it from causing the illness.

It is the act of administering a vaccine, while immunization is the process of building up immunity to a particular disease. Immunizing refers to the introduction of microbes to any medium which, in this instance, it is the same as vaccination.


Vaccines traditionally used the whole or a small portion (containing antibodies) of the pathogen that causes the disease to immunize. Today, new vaccines that utilize genetic technology was developed in the COVID pandemic and are currently being offered in a variety of countries.

Whole microbe vaccines

killed (Inactivated) – The vaccines contain the entire organism, but they are destroyed and activated by chemicals or heat to ensure that they do not cause any illness, but are detected by the immune system of the body. For instance, injectable vaccines are to treat influenza (flu) and pertussis (whooping cough), and Hepatitis A as well as polio and rabies. These COVID vaccines Covaxin (Bharat Biotech-ICMR-NIV India) as well as the Sinovac/Sinopharm vaccines, China are vaccines that kill.

Lively weakened also known as live attenuated. These vaccines include the virus in an extremely weak form and are therefore not capable of causing disease (or sometimes, causing very minor symptoms). For instance, injectable vaccines against tuberculosis ( BCG) as well as measles, mumps rubella ( MMR) and chickenpox (Varicella), and rotavirus. These are in addition to an oral (mouth drops) vaccine for polio oral capsule vaccine against typhoid as well as the spray for nasal use for the flu and COVID in development.

Killed-inactivated as opposed to live-weakened vaccines:

The benefit of an active vaccine is that the organism is able to multiply within the body that the immune system response and production of antibodies is far more robust and durable in comparison to vaccines that are killed which is why booster doses are not likely to be required. In some vaccines that are killed adjuvants (aluminum salts) are added to boost the immune response.

Live vaccines must be avoided by those with immune suppression or compromised immunity who can be given safely. Live vaccines require more rigorous freezing as well as a cold chain. Very rare instances of live pathogens weakening and mutating to an infection (virulent) version have been observed.

Part Microbe Vaccines

Subunit-based vaccines instead of the entire organism, a small portion of it, such as a polysaccharide or protein subunit (containing an antigen) is used to trigger what is needed to trigger an immune response. Subunits of these can be separated from the human body through a chemical disintegration or made in the lab using the use of genetic recombinant technology. Similar to killed vaccines, they are safe for people with weak immune systems and are enriched with adjuvants to boost the immune system’s response. The most common protein subunit vaccinations include acellular pertussis (aP) as well as recombinant Hepatitis B and human virus (HPV) as well as COVID. COVID proteins subunit vaccinations Corbevax (India) and Novovax(India) and NuvaxovidCovovax-India). The polysaccharide subunit vaccines comprise the pneumococcal (PPSV) and meningococcal (Men-ACWY) vaccines.

Conjugate vaccinations are an example of a subunit vaccine that uses a weak antigen (like polysaccharide) is paired with a powerful antigen (like a toxoid or a protein) to act as a carrier, to make sure it is that your immune system can generate more of a reaction against the antigen that is weak. One example of this is the pneumococcal conjugate vaccination (PCV) which is preferred over subunit polysaccharide vaccination, particularly in people with a weak immune system (children) and declining the immune response (elderly). Similar to the meningococcal ACWY vaccine is made up of polysaccharide subunits bonded to the toxoid diphtheria. Other vaccines comprise Hemophilus influenza (Hib) and Typhoid conjugate vaccines.

Toxoid vaccinations consist of inactivated toxic substances (toxoids) produced by certain bacteria that cause the illness and are recognized by the immune system. Some examples are vaccinations for diphtheria and tetanus.

Combining vaccines

Combination vaccines or toxoids, as well as destroyed vaccines (DPT and DaPT) or multiple live vaccines (MMRVmeasles, rubella, mumps, and varicella), are available to provide better effectiveness in immunizations, especially for children.

Certain vaccines come with multiple variants (serotypes) in the viral strain or subunits to provide greater protection. This is the case with the pneumococcal conjugate vaccination (PCV-7 PCV-10, PCV-9, and PCV-13) and the pneumococcal polysaccharide (PPV23) vaccine (PPV23) and the trivalent and the tetravalent flu vaccinations (influenza A and B).

The routes of Vaccination

Most vaccines are delivered in the form of injections, however, certain vaccines can be administered orally (live polio and typhoid vaccinations) or via nasal route (live influenza vaccine). These methods have the benefit of stimulating a strong local immune system in the gut or the respiratory tract and are considered to be the entrance routes for pathogens.

In certain instances of the same infection different kinds and routes of vaccinations might be offered, such as for Typhoid (subunit/conjugate injectable as well as live oral) Polio (killed injectable, live orally), and the flu (killed injectable, live and nasal).

New types of vaccines

The use of the genetic material from viruses to create the needed antigen in our bodies has ushered in a new era in the field of vaccine technology. This is equivalent to creating factories within our bodies to produce the desired antigen in huge quantities to create durable and effective immunity. The immune response is not solely of the production of antibodies (humoral immune system) but also immune cells that cause the destruction of the antigen that causes viral infection (T cells or cell-mediated immune).

Vaccines against COVID are utilizing these latest technologies that allow the production of vaccines much more quickly and with massive production, which has made available clinical trials as well as public vaccination feasible during the epidemic. These vaccines don’t contain live viruses, so they can’t cause disease. They are safe for those even if they suffer from immune suppressive conditions.

Adenoviral vector vaccines

The virus’ genes for the necessary antigen (surface spike proteins in the cases of coronavirus) are transferred into another virus that is inactivated (vector) similar to Adenovirus. The vector is after that, they are in the human body. The body produces antibodies and immune responses to the particular antigen and the vector. So if the vector is an infection to which humans are exposed, there may be antibodies already present against it, which could cause the destruction of the vector prior to the virus’s genes can generate adequate quantities of the antigens required. This is prevented by using vectors with minimal exposure to humans, or that primarily infect animals.

A few examples of vaccines that are approved include the Oxford-Astra-Zeneca COVID vaccine which uses an adenoviral cold virus from Chimpanzees, and the Sputnik Vaccine from Gamaleya, Russia which uses two human Adenoviral varieties (Ad5 as well as 26) and the vaccine developed by Johnson and Johnson using the Ad26 vector.

mRNA vaccines

The genetic information gets transferred (transcripted) by the original viral DNA, or RNA, to the messenger RNA (mRNA) which in turn creates proteins via a process called translation. Injecting the mRNA with the gene information transcripted could create the desired antigenic viral protein in our bodies. This technique allows the production of large amounts of vaccines in a short time.

Examples include COVID vaccines manufactured by Moderna and Pfizer BioNTech.

Plasmid DNA vaccine

The genes that encode information to create the required antigen for viruses are introduced in the DNA molecules, known as plasmids. They are that are found in bacteria. The plasmids are then implanted into humans.

A COVID vaccine developed by Zydus-Cadila dubbed ZyCoV-D is being developed using this technique in India.


Herd immunity provides a kind of indirect protection against an infection in which the majority of the population is immune to the infection via immunization or through exposure to the disease in itself, thus decreasing the risk of contracting infection for those who haven’t been exposed to or immunized against the disease. It can occur after more than 50-60% of the population is exposed to an infection or has been immunized against it.


Every treatment, medicine, or vaccine may cause adverse negative effects. All vaccines have been thoroughly examined for safety in clinical trials prior to entering the marketplace for use.


In the majority of instances, the vaccines have no or minor side effects such as temporary swelling or pain around the injection site or in the muscles, as well as fatigue or numbness in joints, headaches, or chills. They can also cause fever. These symptoms usually last no longer than a couple of days and rarely require treatment, however, there are occasions when only a few doses of medication to treat fever or pain may be prescribed.


An allergic reaction that may occasionally be severe (called anaphylaxis) is not common. While it is more common in those who have an allergy history but it can also happen in a sudden manner. In some instances, it has been due to the presence of chemicals like polyethylene glycol (PEG) or polysorbates found in vaccines. The symptoms vary from mild localized itching swelling and redness, or itching across the entire body and causing itching, swelling of the lips and lips, sweating, palpitation, and breathlessness. The symptoms can be treated by injecting adrenaline (epinephrine) injections in extreme instances, or with antihistamines in less severe allergic reactions. People with an allergy history have such medications with them and they are readily available in the vaccination centers.

These side effects have been extremely rare in the context of vaccines. They may be observed as little as only a few days or weeks after receiving the vaccine. These include Bell’s Palsy, Guillain-Barre syndrome and meningitis, as well as multiple sclerosis as well as encephalitis, and seizures. Although it is alarming as it might seem, these conditions are rare and most cases of these recover quickly.


Today, COVID is available. Vaccines

The mRNA vaccine developed by Pfizer BioNTech is now authorized for use across the UK, EU, USA, Canada, Israel, UAE and Singapore, and Singapore, while the Moderna mRNA vaccine was accepted for use in the USA, UK, EU, and Canada.

The Oxford-Astra Zeneca Adenoviral Vector Vaccine has been approved within the UK, EU, Argentina, Mexico, and India (called Covishieldin collaboration with Serum Institute, Pune), and the Sputnik Adenoviral Vector Vaccine is accepted within Russia (and also in India through the help of Dr. Reddy’s Labs) and in the UAE. Single-dose adenoviral vaccination from Johnson and Johnson has recently been approved in the USA as well as the EU.

Of the vaccines killed-inactivated, India has granted an urgent conditional authorization to its native COVID vaccine Covaxin (a collaboration of Bharat Biotech, a well-acknowledged Indian manufacturer of vaccines, with India’s National Institute of Virology and the Indian Council for Medical Research). Sinovac’s vaccine Sinovac vaccination Coronavac has been approved by China prior to this, while the Sinopharm vaccine Sinopharm is accepted by China, Egypt, Bahrain as well as the UAE.

These vaccines should be given in two doses with the highest level of protection against COVID beginning approximately 2 weeks after receiving the subsequent dose. The interval of dosage is about 4 weeks for these vaccinations but with Astra Zeneca, the Astra Zeneca vaccine, it could take up to 12 weeks.

The mRNA vaccines require strict storage temperatures in deep freeze, whereas Adenoviral vector and killed-inactivated vaccinations are stored at normal temperatures in the refrigerator of 2-8 deg C.

Numerous countries have established collaborations of their local manufacturing businesses with global innovative companies. As of March 20, 2021, approximately 420 million people (starting with frontline and healthcare workers, seniors, and people at risk of complications) all over the world have been vaccinated using different COVID vaccines. Within GAVI ( Global Alliance for Vaccines and Immunisation, WHO) COVID-19 Vaccines Global Access ( COVAX) acts as a platform that supports the development, research, and production of a diverse selection of COVID-19 vaccinations to ensure that all countries participating regardless of income are able to have access to this vaccine when they are made. The goal is to have 2 billion doses of COVID-19 available by 2021’s end for everyone at risk, vulnerable patients, as well as health workers on the frontline.

COVID-related Vaccines: Facts and Concerns

(a) These are new vaccines: It’s normal for people to be concerned regarding COVID vaccines because of their innovative technology and speedy development. But, these innovative technologies have been under development for quite a while. As mRNA vaccines are utilized for the first time by humans in COVID They have also been tested successfully in veterinary practice and tested on humans previously to detect the Zika virus. The adenoviral vector-based vaccine is already being evaluated in humans against the Ebola virus as well as malaria.

B) Have they been examined enough?: The vaccines used to treat COVID have gone through strict phase 2 and phase 3 clinical studies on thousands of individuals who have been able to confirm the neutralizing antibodies produced and the ability to prevent people suffering from COVID. The findings from a variety of research studies are accessible in the public domain as well as some are being evaluated by peer review. Participants in these clinical trials will be monitored to determine the safety and long-term protection against infection.

C) How long will the immunity last?: At present, the immune system is believed to last from 6 months to even a full year the actual effectiveness and safety, as well as the length of time that protective immunity lasts for the general population, will be constantly and carefully observed. Based on the data and recommendations for booster shots are expected to be announced.

D) What about the new COVID strains?: At the present, there isn’t any evidence that suggests that the vaccines are not effective against different strains, even though the level of protection that is developed could differ. If there are major mutations that are expected to occur in the near future of COVID-19, the vaccines might be updated to meet the new requirements.

E) Are they safe and what are the likely adverse reactions: As with the majority of vaccines available some of the mentioned adverse negative effects have been reported during clinical trials of these COVID vaccines but they are not severe and have demonstrated the ability to recover. A high degree of safety throughout every stage of the trial is documented for these vaccines.

(f) Who should take the vaccine: In the case of an ongoing epidemic, it is recommended for everyone to get any vaccine that is available most quickly, as these vaccines don’t differ greatly in their effectiveness or security. These vaccines all protect against the possibility of contracting COVID and its potential complications and death. Health care professionals or frontline workers, as well as the elderly, particularly those with comorbidities, need to be the first to receive the vaccine during the program. Anyone who has had COVID should get the vaccine but only after a full recovery. Individuals with a compromised immune system or taking medication to suppress their immune system may not be able to produce the same immune response, however, they should nevertheless get the vaccine as some protection is more effective than none, and is particularly to reduce the risk of complications and even death.

The advantages of taking vaccinations and being protected surpass the risks and harm of suffering from COVID.

A lot of vaccinations received an emergency use approval (EUA) from the regulatory authorities of different countries following thorough scrutiny and examination of the efficacy of trials and safety information. The vaccination program against COVID is in full force in a number of countries. The public vaccination program has been started by health professionals and front-line employees, high-risk populations such as the elderly or those who have comorbidities, and the vaccine will then be distributed to the general population.

Other vaccines that are recommended apart from COVID must be administered at an interval of 2 weeks (preferably 4 weeks in the case of live vaccines) before or following taking the COVID vaccination dose.

When it comes to COVID vaccines, one of the questions people ask is how they can cause a mask, and social distancing shows up after a person has been vaccinated. The answer is in the reality that post-vaccination, you may be an asymptomatic carrier, so it is possible that you do not have COVID, but you could pass it on to someone otherwise unaffected or does not possess protection from the natural immunity or vaccination. To reach the point of normalcy pre-COVID increasing numbers of individuals will require the vaccine in order to gain herd immunity.

Important aspects to consider when vaccinating COVID

The time period from 10 days to two weeks following the vaccination is typically a time in which your body’s immune reaction and the production of antibodies occurs. This means that at this point it is possible that the patient will be at risk of contracting the disease because the protection against infection is not yet at its optimal level. It is important to get all recommended doses to get a good immunization. If you have suffered from COVID the dose of vaccine can be administered between 4 and 12 weeks after recovery.

Other vaccines, if required, apart from COVID must be administered at an interval of two months (preferably four weeks for vaccines that live) prior to or following taking the COVID vaccination dose. After vaccination, blood donation may be performed after a period of 14 days.

When it comes to COVID vaccines, the question that pops up in the minds of many is whether should wear masks in public or whether social distancing cease after a person has been vaccine-vaccinated. The answer is on the basis that after vaccination, one may be an asymptomatic carrier, so there is a chance that one does not contract COVID, but could pass it on to someone who was not previously exposed or does not be protected by natural immunity or vaccination. To reach the point of normalcy pre-COVID, more individuals will need to undergo the vaccination in order to gain effective herd immunity.

Immunization can reduce the risk of suffering from the illness, especially severe infections that require hospitalization or cause complications but it may not be able to stop the asymptomatic transmission. In some individuals, even after a proper vaccination, a sufficient immune response might not be produced in the same way, and it may differ from person to individual. That’s why more citizens in the community need to be vaccinated to ensure that herd immunity is able to provide complete and effective protection against infection in the population, as well as protect those who are vulnerable.

The benefits of vaccinating people and the entire community exceed the risks and adverse impacts. The effectiveness of vaccination has been proven in preventing and curing many infections across the globe and is a scientifically validated, established, and recommended method.

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