As the US is rushing to vaccinate its citizens to stem the wave of increasing daily Covid-19 infectious and mortality rate, evidence has emerged that suggests some recipients of the doses of the vaccines have shown allergic reactions.
The US Centres for Disease Control and Prevention (CDC) last week said its ‘early safety monitoring’ system has detected 21 cases of anaphylaxis or allergic reactions to the Covid-19 vaccines developed by Pfizer Inc and Moderna Inc.
The two pharmaceuticals companies were the first to be cleared to provide vaccines to inoculate the Americans population against the pandemic. The centre said it also noted ‘less severe non-allergic reactions’ cases, adding it is monitoring the developments very closely.
Officials from the centre said the cases were reported after administering 1,893,360 first doses of Pfizer-BioNTech COVID-19 vaccine between 14 December and 23 December in 2020. This translates into 11.1 cases per million vaccine doses administered, according to the officials. They said this compared with flu vaccines in which such reactions occur at a rate of 1.3 per million shots.
According to the CDC officials 28 people who received the Pfizer-BioNTech vaccine presented severe allergic reactions and it also noted one similar case, which can cause throat swelling and breathing difficulty after an individual has received Moderna’s vaccine.
In explaining the difference, the officials said this is due to fact that the Pfizer-BioNTech vaccine was authorised earlier than the Moderna.
But the centre moved to allay fears saying the severe reactions are extremely rare and urged people to get vaccinated to prevent more deaths from the virus, which is killing Americans by their thousands.
In addition, the CDC also called for more precautions. It urged centres that provide the vaccine to be adequately prepared to identify severe reactions and that the staff should be trained on how to recognise when an individual needs to be referred to hospitals for further attention.
It was also discovered that 86% of severe anaphylaxis cases “had symptom onset within 30 minutes of vaccination, and that 81% persons with anaphylaxis had a history of allergies or allergic reactions, including some with previous anaphylaxis events”.
The centre further indicated that: “90% of the reported anaphylaxis cases after receipt of Pfizer-BioNTech COVID-19 vaccine occurred in women, although 64% of the vaccine doses administered with sex of recipient recorded were given in women.”
Officials said the reason for this could be due to the fact that more women than men had received a first dose of Pfizer-BioNTech COVID-19 vaccine during the period under review.