Why do we need a vaccine?
The development of vaccines against common infections has been the single most important public health intervention to date. Vaccines prevent illness and save lives. Vaccination to protect South Africans from COVID-19 disease; especially severe disease, is critical to halt the devastating effects of the pandemic. By getting vaccinated you are not only protecting yourself but also your loved ones and South Africans at large.
What vaccines are available?
Several safe and effective COVID-19 vaccines are already being rolled out across the world. There are three different technologies that have been used to create these vaccines:
- mRNA vaccines (Moderna and Pfizer BioNTech)
- Viral vector vaccines (AstraZeneca Oxford chimpanzee adenovirus, Johnson&Johnson, Sputnik, Sinovac)
- Protein subunit vaccines (Novavax)
At present South Africa is planning to roll-out the Johnson&Johnson vaccine to its healthcare workers first.
COVID-19 vaccine-related severe allergic reactions
Severe, potentially life-threatening, reactions (anaphylaxis) to vaccines occur once in a million vaccinations. Unfortunately, as the mRNA vaccines have been rolled out across the globe there have been cases of severe allergic reactions following the dose. Current data suggest a 1 in 100 000 to 1 in occurrence of severe reactions. Anaphylaxis to vaccination is usually due to either the specific way the vaccine is manufactured or to a component of the vaccine. Unlike some other vaccines the current COVID-19 vaccines do not contain food-related components such as egg or gelatin. It is current thinking that the cause for severe reactions in the Pfizer-BioNtech vaccine is due to Polyethylene glycol (PEG) 2000 allergy.
Am I at risk of a severe allergic reaction to the COVID-19 vaccine?
Although individuals with allergies might feel worried about having a COVID-19 vaccine it must be said that the benefits to the individual and the public greatly outweigh the risk! We all need to work together to get the majority of the population vaccinated as soon as possible. After looking at the available information and the manufacturing and content of the various vaccines we advise the following:
These patient groups can be vaccinated routinely ie no testing or additional precautions need to be followed:
a) Food allergies including anaphylaxis to foods e.g., nuts, shellfish, egg or milk.
b) Environmental allergy e.g. house dust mite, pollen or animal danders.
c) Severe reactions to bee or wasp stings.
d) Allergy to penicillin or other antibiotics.
e) Patients receiving allergen immunotherapy.
f) Patients that had urticaria that occurred several days after different vaccines, treated only with a few days of antihistamines.
For these persons vaccinations can occur in a standard setting with a 30 minute observation time.
Who needs assessment before having the vaccine?
People with prior anaphylaxis to a vaccine, e.g., influenza, and people with underlying mast-cell disorders associated with recurrent anaphylaxis to medications, may be at higher risk and should be referred to an allergist/allergologist for risk assessment that may include specific testing to determine the offending ingredient and advise about the safe use of a specific COVID-19 vaccine. In most of these instances’ people will be able to safely receive COVID-19 vaccination
Who should NOT receive a COVID-19 vaccination?
The only reason to NOT receive a COVID-19 vaccination is either that the person has a known allergy to one of the ingredients in the vaccine e.g. PEG 2000 or if someone had a severe reaction to a prior COVID-19 vaccination. These individuals should see an allergologist.
People with prior anaphylaxis to a vaccine, e.g., influenza, and people with underlying mast-cell disorders associated with recurrent anaphylaxis to medications, may be at higher risk and should be referred to an allergologist for risk assessment that may include specific testing to determine the offending ingredient and advise about the safe use of a specific COVID-19 vaccine. In most of these instances’ people will be able to safely receive COVID-19 vaccination
Table 2. Recommended COVID-19 (non-live) vaccine management in different allergy groups
*Allergy assessment should focus on the previous vaccine-related anaphylaxis and identification of the offending vaccine component, most commonly an excipient. Any possibility of a previous reaction to polysorbate 80 (component in the AstraZeneca Oxford COVID19 vaccine) or polyethylglycol (PEG) 2000 – a component in the Pfizer BioNtech vaccine should warrant skin testing for PEG and polysorbate, and low dose vaccine challenge under supervision.
Similarly, if anaphylaxis occurs to the 1st dose of COVID19 vaccine patients should undergo full allergy assessment including testing for PEG and polysorbate sensitivity.