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WHO approved Vaccines
Institutions and manufacturers started to work on the development of Covid-19 vaccines only after the declaration of the Public Health Emergency of International Concern (PHEIC) by the WHO.
Moderna: mRNA-1273
- Vaccine Type – RNA
- Trial Phase – Approved
- Who should get vaccinated? The Moderna vaccine is recommended for people aged 18 years and older.
- Recommended dosage – SAGE recommends the use of the Moderna mRNA-1273 vaccine at a schedule of two doses (100 µg, 0.5 ml each) 28 days apart. If necessary, the interval between the doses may be extended to 42 days. Compliance with the full schedule is recommended and the same product should be used for both doses.
- How efficacious is the vaccine? The Moderna vaccine has been shown to have an efficacy of approximately 94.1 per cent in protecting -against COVID-19, starting 14 days after the first dose.
- Who should not get vaccinated? Individuals with a history of severe allergic reaction* to any component of the vaccine should not take this or any other mRNA vaccine. While vaccination is recommended for older persons due to the high risk of severe COVID-19 and death, very frail older persons with an anticipated life expectancy of fewer than 3 months should be individually assessed. The vaccine should not be administered to persons younger than 18 years of age pending the results of further studies
* An immediate allergic reaction means a reaction within 4 hours of getting the shot, including symptoms such as hives, swelling, or wheezing (respiratory distress).
- Side effects – Cases of myocarditis and pericarditis in adolescents and young adults have been reported more often after getting the second dose than after the first dose of the mRNA COVID-19 vaccine, Moderna.
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Pfizer/BioNTech: BNT162b2
- Vaccine Type – RNA
- Trial Phase – Approved
- How does Pfizer work? mRNA, delivered to your body’s cells by lipid nanoparticles, instructs the cells to generate the spike protein found on the surface of the novel coronavirus that initiates infection. Instructing cells to generate the spike protein spurs an immune response, including the generation of antibodies specific to the SARS-CoV-2 spike protein. mRNA vaccines do not contain any virus particles, meaning that they don’t contain weakened or dead parts of a virus or bacterium.
- Who should not take the vaccine? People with a history of severe allergic reactions to any component of the vaccine should not take it. There are currently no efficacy or safety data for children below the age of 12 years. Until such data are available, individuals below 12 years of age should not be routinely vaccinated.
- Recommended dosage – A protective effect starts to develop 12 days after the first dose, but full protection requires two doses which WHO recommends be administered with a 21 to 28-day interval.
- Efficacy- The Pfizer BioNTech vaccine against COVID-19 has an efficacy of 95% against symptomatic SARS-CoV-2 infection.
- Side effects – There is a remote chance that the Pfizer-BioNTech COVID-19 Vaccine could cause a severe allergic reaction. A severe allergic reaction would usually occur within a few minutes to one hour after getting a dose of the Pfizer-BioNTech COVID-19 Vaccine. Signs of a severe allergic reaction can include difficulty breathing, swelling of your face and throat, a fast heartbeat, a bad rash all over your body, dizziness, and weakness. Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining outside the heart) have occurred in some people who have received the Pfizer-BioNTech COVID-19 Vaccine. In most of these people, symptoms began within a few days following receipt of the second dose of the Pfizer-BioNTech COVID-19 Vaccine. The chance of having this occur is very low.
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Janssen (Johnson & Johnson): Ad26.COV2.S
- Vaccine Type – Non-Replicating Viral Vector
- Trial Phase – Approved
- How does it work? Viral vector vaccines use a modified version of a different virus (the vector) to deliver important instructions to our cells.
- Who should not get vaccinated? Individuals with a history of anaphylaxis to any component of the vaccine should not take it. Anyone with a body temperature over 38.5ºC should postpone vaccination until they no longer have a fever. The vaccine is not recommended for persons younger than 18 years of age pending the results of further studies in that age group.
- Recommended dosage– SAGE recommends the use of Janssen Ad26.CoV2.S as one dose (0.5 ml) given intramuscularly. There should be a minimum interval of 14 days between the administration of this vaccine and any other vaccine against other health conditions. This recommendation may be amended as data on co-administration with other vaccines become available.
- Efficacy- 28 days after inoculation Janssen Ad26.CoV2.S was found to have an efficacy of 85.4% against severe disease and 93.1 % against hospitalization. A single dose of Janssen Ad26.COV2.S was found in clinical trials to have an efficacy of 66.9% against symptomatic moderate and severe SARS-CoV-2 infection.
- Side effects – As of April 23, 2021, experts reviewing safety reports for this vaccine found 15 reports of women who got the J&J/Janssen COVID-19 Vaccine and later developed thrombosis with thrombocytopenia syndrome (TTS). TTS is a serious condition that involves blood clots with low platelets. These reports represent a reporting rate of 7 such events per 1 million vaccinations among women 18 through 49 years old and a rate of 0.9 per 1 million vaccinations among women 50 years and older. For all women, this is a rare adverse event. For women 50 years and older and men of all ages, the adverse event is even rarer.
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Oxford-AstraZeneca: AZD1222
- Vaccine Type – Non-Replicating Viral Vector
- Trial Phase – Approved
- What is AstraZeneca? COVID-19 Vaccine AstraZeneca is a vaccine used to protect people aged 18 years and older against COVID-19, which can cause serious illness and even death. It prepares your immune system to identify and destroy the coronavirus, SARS-CoV-2, the virus which causes the disease COVID-19. The vaccine delivers a modified common cold virus containing the genetic code for the coronavirus spike protein. These spike proteins protrude from the outside of coronaviruses and help them infect cells within the human body. This “modified virus” technology has been rigorously tested and successfully used to make vaccines for other diseases.
- How was the vaccine tested? Although the testing of coronavirus vaccines has been faster than usual because the pandemic is a major public health emergency, no risks have been taken with vaccine safety. Worldwide, over 60,000 people have taken part in testing this vaccine through clinical trials and the vaccine has been shown to be highly effective against all severities of COVID-19 and across all adult age groups. Regulatory agencies that approve medicines have clear and strict rules for the approval of any new medicine and the vaccine has now been granted emergency or conditional use approval in over 70 countries.
- Efficiency – AZD1222 vaccine against COVID-19 has an efficacy of 63.09% against symptomatic SARS-CoV-2 infection.
- Recommended dosage – The recommended dosage is two doses given intramuscularly (0.5ml each) with an interval of 8 to 12 weeks.
- Vaccine not recommended – For People with a history of severe allergic reaction to any component of the vaccine and persons younger than 18 years of age pending the results of further studies.
- Side effects – According to AstraZeneca, of the more than 17 million people given the vaccine across the EU and UK so far, there had been 15 events of deep vein thrombosis and 22 events of pulmonary embolism reported as of 8 March. “This is much lower than would be expected to occur naturally in a general population of this size and is similar across other licensed COVID-19 vaccines,” the company said.
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Covishield (Oxford/AstraZeneca formulation)
- Vaccine Type – Non-Replicating Viral Vector
- Trial Phase – Approved
- Who should get the vaccine? The vaccine has been approved for restricted use in emergency situations in individuals 18 years or older.
- Who should not get the vaccine? You should not get the vaccine if you had a severe allergic reaction after receiving the first dose of this vaccine or if you are allergic to any ingredient of this vaccine.
- Recommended dosage – The COVISHIELD Vaccine will be given to you as an intramuscular (IM) injection only, preferably in the deltoid muscle. The COVISHIELD vaccination course consists of two separate doses of 0.5 ml each, between 4 and 12 weeks apart.
- Side effects – There are no major safety concerns regarding this vaccine. The most common side effects with COVID-19 Vaccine AstraZeneca (which may affect more than 1 in 10 people) were tenderness, pain, warmth, redness, itching, swelling or bruising where the injection is given, generally feeling unwell, feeling tired (fatigue), chills or feeling feverish, headache, feeling sick (nausea), joint pain or muscle ache. In clinical studies, most side effects were mild to moderate in nature and resolved within a few days with some still present a week after vaccination.
- Efficacy – The first interim safety and efficacy data for a viral vector coronavirus vaccine, ChAdOx1 nCoV-19, was evaluated in four trials across three continents, showing significant vaccine efficacy of 70·4% after two doses and protection of 64·1% after at least one standard dose, against symptomatic disease, with no safety concerns.
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Sinopharm (Beijing): BBIBP-CorV (Vero Cells)
- Vaccine Type – Inactivated
- Trial Phase – Approved
- What is a Sinopharm BIBP vaccine? Sinopharm/BIBP COVID-19 vaccine is an inactivated vaccine that consists of virus particles that have been grown in culture and then were inactivated to lose disease-producing capacity, while still stimulating an immune response.
- Who should get the vaccine? Sinopharm/BIBP COVID-19 vaccine is indicated in individuals aged 18 years and above
- Who should not get the vaccine? Individuals with a history of anaphylaxis to any component of the vaccine should not take it. Anyone with a body temperature over 38.5ºC should postpone vaccination until they no longer have a fever.
* Vaccination should be postponed in individuals suffering from acute severe febrile illness, or acute infection [Ministerio de Salud de Perú, 2021 ]
- Recommended dosage – SAGE recommends the use of the BIBP vaccine as 2 doses (0.5 ml) given intramuscularly. WHO recommends an interval of 3–4 weeks between the first and second dose. If the second dose is administered less than 3 weeks after the first, the dose does not need to be repeated. If the administration of the second dose is delayed beyond 4 weeks, it should be given at the earliest possible opportunity. It is recommended that all vaccinated individuals receive two doses.
- How does this vaccine compare to other vaccines already in use? We cannot compare the vaccines head-to-head due to the different approaches taken in designing the respective studies, but overall, all of the vaccines that have achieved WHO Emergency Use Listing are highly effective in preventing severe disease and hospitalization due to COVID-19.
- Efficacy- large multi-country Phase 3 trial has shown that 2 doses, administered at an interval of 21 days, have an efficacy of 79% against symptomatic SARS-CoV-2 infection 14 or more days after the second dose. Vaccine efficacy against hospitalization was 79%.
- Side Effects – The 1st and 2nd dose post-vaccination side effects were mild, predictable, and there were no hospitalization cases, this data will help to reduce the vaccine hesitancy. This was from a study conducted among the Sinopharm vaccinated UAE population.
The WHO identified two serious adverse events that were possibly linked to the vaccine — serious nausea and a rare neurological disorder known as acute disseminated encephalomyelitis. There was also one diagnosis of thrombus (blood clot) in the vaccine group.
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Sinovac: CoronaVac
- Vaccine Type – Inactivated
- Trial Phase – Approved
- What is a SINOVAC (CoronaVac) Vaccine? The CoronaVac vaccine is an inactivated vaccine that uses a whole virus structure consisting of spike (S), nucleocapsid (N), membrane (M) and envelope (E) proteins as vaccine targets (Dai and Gao, 2021). As a result, the antibody response elicited by CoronaVac is directed not only against the S protein but also against many other SARS-CoV-2 antigens.
CoronaVac is an inactivated vaccine. It uses a dead version of the SARS-CoV-2 virus so that it cannot replicate, but it keeps the surface spike protein intact to trigger the body’s immune system to create antibodies for protection against the live virus if it were to invade.
- Who is the vaccine not recommended for? The vaccine is not recommended for persons younger than 18 years of age, pending the results of further studies in that age group. Individuals with a history of anaphylaxis to any component of the vaccine should not take it. Persons with acute PCR-confirmed COVID-19 should not be vaccinated until after they have recovered from acute illness and the criteria for ending isolation have been met. Anyone with a body temperature over 38.5°C should postpone vaccination until they no longer have a fever.
- Recommended dosage – SAGE recommends the use of the Sinovac-CoronaVac vaccine as 2 doses (0.5 ml) given intramuscularly. WHO recommends an interval of 2–4 weeks between the first and second dose. It is recommended that all vaccinated individuals receive two doses. If the second dose is administered less than 2 weeks after the first, the dose does not need to be repeated. If the administration of the second dose is delayed beyond 4 weeks, it should be given at the earliest possible opportunity.
- Efficacy – A large phase 3 trial in Brazil showed that two doses, administered at an interval of 14 days, had an efficacy of 51% against symptomatic SARS-CoV-2 infection, 100% against severe COVID-19, and 100% against hospitalization starting 14 days after receiving the second dose.
- Side Effects – Phase 1 and 2 clinical trial data for the vaccine, published in The LancetTrusted Source in February 2021, reveal some of the side effects reported by trial participants. According to the data, the most common side effect reported within 28 days of the second dose was injection-site pain (13–21%, depending on the dosing schedule). Injection site reactions are common with other COVID-19 vaccines. Other side effects included fatigue, diarrhoea, and muscle pain. Most of these side effects were mild and lasted only for 2 days. Additionally, the paper notes that participants who received CoronaVac reported a lower occurrence of fever in comparison to other COVID-19 vaccines, including the mRNA-based vaccine from Moderna and viral vector vaccines from Oxford-AstraZeneca and CanSino.
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Vaccine Categories & Types
Component Viral Vaccines
- Protein Subunit: Contains isolated and purified viral proteins
- Virus-like particles (VLP): Contains viral proteins that mimic the structure of the virus, but no genetic material
- DNA-based and RNA-based: Contains viral genetic material (such as mRNA) which provides the instructions for making viral proteins
- Non-Replicated Viral Vector: Contains viral genetic material packaged inside another harmless virus that cannot copy itself
- Replicating Viral Vector: Contains viral genetic material packaged inside another harmless virus that can copy itself
Whole Virus Vaccines
- Inactivated: Contains copies of the virus that have been killed (inactivated)
- Live-Attenuated: Contains copies of the virus that have been weakened (attenuated)
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