4. Covid Vaccines

SARS-CoV-2: Type of Virus and Transmission

RNA virus (Coronaviridae family)

• includes MERS-CoV(MERS), SARS-CoV-1 (SARS)

Transmission: primarily by droplets spread through coughing, sneezing or talking; lesser degree via contaminated surfaces

SARS-CoV-2: Symptoms and Complications

fever, cough, shortness of breath (additional symptoms include weakness, fatigue, nausea, vomiting, diarrhea, changes to taste and smell)

Complications include impaired function of the heart, brain, lung, kidney and coagulation system

• Long COVID?

• ~17-35% of hospitalized patients treated in an ICU

Long Covid Defintion

Include a wide range of symptoms that can potentially last weeks to years post-exposure

• Financial burden of these patient is not yet well understood

• More common in those who had severe COVID

• Some data suggest that those vaccinated who get COVID may be less at risk

Long Covid Symptoms

Fatigue that interferes with daily activities

Symptoms worsen with physical or mental activity

Fever

Cough with shortness of breath

Chest pain

Heart palpitations

Headaches

Sleep problems

GI issues

Joint and muscle pains

What we watch for in covid variants

variants that impact:

• Transmissibility

• Immunity to vaccines

• Infection Severity

WHO divides variants into:

• Variants of concern

• Variants of interest

Current variants of concern and interest

No variants of concern right now

One currently circulating variant of interest:

JN.1 (Genetic features of BA.2.86 + S:L455S):

• descendent lineage of BA.2.86

• Growth advantage: High

• Immune Escape: Moderate

• Severity: Low

Vaccine development has focused predominatley on what for Covid? Why?

focused predominantly on the viral structural spike (S) protein of SARS-CoV-2

Facilitates entry into the cell and is located on the surface of the virion, and was identified within weeks of first identification of cases

most common covid vaccine used in north america

mRNA

Classical platforms for COVID-19 Vaccines

Whole-inactivated virus (phase 1)

Live-attenuated virus (pre-clinical)

Protein subunit (Phase ½ clinical trials)

Virus-like particle (pre-clinical stage)

Next-genetation platforms for COVID-19 Vaccines

Viral vector (Phase1/2/3)

DNA (Phase 1)

RNA (Phase1/2)

Antigen-presenting cells (Phase 1/2)

Types of COVID Vaccine (moderna, pfizer not included)

eek

Most common correlate of protection in COVID vaccines and target of all COvid vaccines

Neutralizing Ab titers (NtAb)

Target is the spike protein regardless of vaccine type

COVID-19 Vaccine Efficetiveness

the short-term relative vaccine effectiveness of XBB. 1.5 mRNA COVID-19 vaccines in adults has been estimated to be approximately:

• 50 to 60% against symptomatic disease and 60 to 70% against hospitalization

NACI Covid Vaccine Recommendations for patients at increased risk of COVID infections are

• All adults 65 years of age or older
  

• Those 6 months of age and older who are:

  • Residents of long term care, people with underlying medical conditions, pregnant, First Nations, people who provide essential care

These patients SHOULD receive a second dose of COVID 19 vaccine per year

>80 years of Age, long term care and aggregate living adults, those 6 months and older who are immunocompromised

Timing of doses is left up to provincial bodies dependent on epidemiological patterns and other factors though suggestion for access in spring and fall

These patients MAY receive a second dose of COVID 19 vaccine per year

Adults 65-75

Myth: “vaccine was developed too fast” explained

mRNA vaccines have been in the works for years. Only the massive funding and urgency allowed them to cut out time between research stages. mRNA vaccines are also much easier to design and roll out than traditional vaccines

Myth: “mRNA vaccines change your DNA” explained

mRNA is simply a message that your body reads. Your cells produce millions of mRNA strands every day. They cannot insert into your DNA and cannot even enter the nucleus.

Myth: “Pfizer director admits ‘vaccine’ wasn’t tested for transmissibility.” explained

Vaccines were not required to test for this when being developed. It would of added time to a process that was already under pressure. The focus was on preventing illness, hospitalization and death. It only makes sense that if you reduce infection rates transmission will also drop. Some studies in Israel and the UK did show a significant reduction in transmission (>75%)

Myth: “mRNA vaccines have dangerous components” explained

mRNA vaccines are free of preservatives. Contain only the mRNA strand a phospholipid layer to stabilize and allow absorption and PEG salts and sugars to make the solution isotonic. There are no fetal cells or other products as the mRNA is produced in an mRNA fabricator.

Myth: “It’s not safe until we have more long-term data” explained

With billions of people vaccinated, many having been vaccinated almost a 2 years ago with no issues. The mRNA itself is gone from your system 2-6 weeks after injection.