Vaccine technologies

Virus-based and protein-based vaccinations make up most vaccines now approved for human use. Below is an overview of the several COVID-19 vaccine platforms currently being developed.

RNA based COVID 19 vaccine

 The mRNA of the SARS CoV 2 is encapsulated in lipid nanoparticles (LNP). The LNP is a vehicle to deliver the viral RNA into the host cell.

Pfizer-BioNTech and Moderna COVID 19 Vaccines are encapsulated mRNA vaccines

Pros

• Easy and quick to design
• Large scale production

Cons

• New technology
• Problems with stability

Viral vector vaccine

Viral vector vaccines use a modified version of a different virus as a vector to deliver immunity.

COVID 19 vaccines from Janssen and Oxford-AstraZeneca are viral vector vaccines.

Pros

• Produced without handling live virus. 
• Familiar, proven technology
• Good immuneresponse

Cons

• Previous exposure to the vector could reduce effectiveness.
• Prime-boost regimens
• Relatively complex to manufacture.

The Sputnik V vaccineuses anadenoviral vector base to transport SARS CoV 2 genetic material into the host cell. Human adenoviruses can be engineered touse as vectors.

General Precautions

Individuals with a history of anaphylaxis and immediate allergic reactions to

• Other vaccines or injectables that are not mRNA vaccines.

• Vaccine components like polyethylene glycol, polysorbate or any other additives

Do not get vaccinated if you are:

• Having COVID 19 infection.
• Have a fever (body temperature more than 38.5°C)

Possible Side Effects

• Pain, redness, swelling at the injection site.
• Tiredness
• Headache
• Muscle or Joint Aches
• Chills
• Fever
• Nausea

Vaccination in Special population

Pediatrics

Comirnaty (Pfizer) is the first COVID-19 vaccine approved for children aged 12 years and above.

Current vaccines that are approved for children over 12 years of age include

• Comirnaty (Pfizer-BioNTech)
• Moderna
• Sinopharm
• Sinovac
• Covaxin

Cuba is the first country to vaccinate children aged two years and above with the Abdala and Soberana vaccines. These vaccines are not recognised by the WHO and have not undergone International scientific review. The clinical trial results of these vaccines have yet to be published.CDC recommends everyone stay up to date with COVID-19 vaccines for their age group:

• Children and teens aged six months–17 years
• Adults aged 18 years and older

The pediatric age range varies depending on the vaccine, clinical trials, and approval in different countries.

Pregnancy and Lactation

The American College of Obstetricians and Gynecologists (ACOG) has issued guidelines regarding vaccinating pregnant and lactating mothers.

• Do not withhold COVID-19 vaccines from pregnant women. 
• Although a conversation with a clinician may be helpful.
• A benefit-risk assessment should be made.
• Safe in lactating mothers

Immunocompromised Persons

Available data are currently insufficient to assess vaccine efficacy or vaccine-associated risks in severely immunocompromised persons, including those receiving immunosuppressant therapies. The immune response to the vaccine may be reduced, lowering its clinical effectiveness.

Booster Shots

A booster dose of vaccine is administered when the initial, sufficient immune response to a primary vaccine series is likely to have waned over time.

Booster doses are currently approved for many vaccines. The efficacy of booster doses of some vaccines is still being tested.

People aged over 16 years are eligible for boosters, given a favourable benefit-risk assessment.

Additional Dose

Administration of a second vaccine dose when the initial immune response following a primary vaccine series is likely to be inadequate.

• It is recommended that immunocompromised individuals aged 12 years (Pfizer-BioNTech) or 18 years (Moderna) who have completed an mRNA COVID-19 vaccine primary series receive an additional mRNA vaccine dose at least 28 days after their second dose.
• The recommendation does not apply to immunocompromised recipients of the Janssen COVID-19 vaccine; these people should follow the booster dose recommendations.
• Additional doses of other vaccines are being studied.

More than 200 additional vaccine candidates are in development, of which more than 60 are in the clinical development stage. Even if you have been vaccinated, you should continue to take precautions to prevent the spread of the disease.

• Keep at least 1 metre from others.
• Wear a mask, especially in crowded, closed, and poorly ventilated settings.
• Clean your hands frequently.
• Cover up any cough or sneeze with your bent elbow.
• When indoors with others, ensure good ventilation, such as by opening a window.

So, what are you waiting for? 

Get vaccinated!! And as pharmacists, we can create awareness about the importance of vaccination, encourage the community to get vaccinated and promote safety measures against COVID-19. 

Fathima Shameen, Pharm D

Clinical Pharmacist

Infectious Diseases Forum