FAQ about the COVID 19 Vaccine Part 2

 

1.      1. Why do people faint after taking the vaccine?

Fainting, also called syncope, describes the loss of consciousness usually caused by a reduction in blood flow to the brain (CDC, 2020).  Fainting may be triggered by  vaccinations and other medical procedures for a variety of reasons including anxiety.  Additionally, one reasonable explanation for fainting after a vaccination is the stimulation of the vagus nerve which can cause the heart rate to slow down and the blood pressure to drop drastically (Brouhard, 2019).   This stimulation may be also be a result of the fear and anxiety associated with the pain from injection needles.  One report from the vaccine adverse event group reporting system (VAERS) found that 62% of syncope reports were among adolescents 11 to 18 years.  The CDC recommends that if a person faints after vaccination, he or she should be carefully guided to the floor to prevent fall injury and should be closely monitored until he or she has regained consciousness.  Similarly, after vaccination, it is recommended that  patients are observed for 15-20 minutes in the event that a delayed vagal response is triggered. 

 

2.      2. Can I take the vaccine if I am pregnant and /or breastfeeding?

 

Pregnant women are listed among the special populations that are at increased risk for severe Covid-19 infections.  In fact, the Covid-19 infection is associated with an increased risk of preterm birth compared to women who are not infected with the virus (CDC, 2020).   However, the available data on the available  vaccines is insufficient to assess the true safety and efficacy when used in pregnant women, especially as it relates to vaccine-associated risk to the mother or to the unborn child.  This is because the clinical trials conducted did not include pregnant and breastfeeding women and most animal developmental and toxicity studies are still in progress. Additionally, candidates who become pregnant during the clinical trials  will and are still being monitored to assess for short-term and long-term effects, efficacy and safety.  Still, the CDC recommends and encourages women who are pregnant and lactating and who are at high risk of exposure to be vaccinated. This is because, in general, vaccinations allow mothers to develop antibodies that may cross the placenta to help protect babies against serious illnesses, this is called cocooning, (CDC, 2021:APhA Training Module 2020). 

Additionally, the mRNA technology used in the Pfizer and Moderna Vaccines are not incorporated in the cell DNA and so are expected to pose minimal risk to the pregnant population and to the child (in-utero or during breastfeeding).   It is currently unknown whether these vaccines are secreted in breast milk (CDC, 2021). 

 

3.   3. Which Vaccine should I get? Moderna, Pfizer, Johnson & Johnson, or Oxford-AstraZeneca??

The Pfizer-BioNTech and Moderna Covid-19 vaccines were given Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA) in mid-December  of 2020 (CDC, 2021).  On Feb. 27, the FDA also approved an Emergency Use Authorization for Johnson & Johnson’s single dose vaccine.   Overall, the efficacy of each vaccine will vary based on the geographical region and the variant of the corona virus. 

Pfizer, in their 2020 report entitled “Pfizer and BioNTech conclude Phase 3 of Covid-19 vaccine candidate, meeting all efficacy endpoint,” reported that primary efficacy analysis of the vaccine showed an efficacy of 95% in preventing symptomatic Covid-19 infection. After two doses and they appeared to be more or less equally protective across age groups and racial and ethnic groups. Similarly, the CDC confirmed that based on evidence from clinical trials, the Moderna vaccine was 94.1% effective at preventing symptomatic Covid-19 after the second dose and also appeared to be equally effective across different ethnic and racial groups.  On the other hand, the Johnson & Johnson single dose vaccine showed variability based on geographic locations  with an average  coverage of 66%  against moderate to severe Covid-19  infections overall from 28 days after injection.  The vaccine showed 72% protection in the United States, 66% in South America and 57% in South Africa (including results from the new variants of the virus) (STAT health, 2020).   Similarly, the AstraZeneca vaccine showed an efficacy of  63.09% against symptomatic Covid-19 infections.  This was reported by the World Health Organization  on February 11, 2021, who also reported that longer dose intervals within a range of 8-12 weeks is associated with greater efficacy when using the AstraZeneca vaccine. 

In essence, the Pfizer and Moderna vaccines have shown equivalent degrees of efficacy during the early phases of the clinical trials when compared to the Johnson & Johnson and AstraZeneca vaccine.  However,  vaccination with either of these vaccines provides some amount of coverage that is needed to achieve individual immunity and  herd immunity  (universal immunization) which  slows the spread of the Covid-19 virus and paves the way for us to move out of this pandemic. 

Authors:

Dr. Winsome B. Christie

Clinical Pharmacist/Integrative

Nathine Morgan  (BPharm candidate)

 March 4, 2021