SINGAPORE, Sept 19 — More than 18,000 doses of Nuvaxovid vaccine have been administered as of Aug 31, with 28 reports of adverse reactions, of which 82 per cent — or 23 cases — were not serious, said the Health Sciences Authority (HSA) in its latest safety update on Covid-19 vaccines today.

Allergic reactions reported from this vaccine included rash and eyelid swelling, numbness, dizziness, chest pains and vasculitis, which is an inflammation of blood vessels.

These were largely consistent with what were reported in the clinical studies or with other Covid-19 vaccines, said HSA.

Of the five serious cases reported, four patients suffered anaphylaxis — a potentially life-threatening allergic reaction — and one had a "serious allergic reaction” from the Nuvaxovid vaccine, which has been available here since May 18.

All five patients have recovered from these reactions, added HSA in its 13th vaccine safety update which covers the period Dec 30, 2020 to Aug 31, 2022.

The authority said these reactions occurred in people who had previous allergic reactions or adverse effects to other Covid-19 vaccines — Pfizer/Comirnaty or Sinovac-CoronaVac — as well as a history of drug or food allergies.

"As with the mRNA vaccines, safeguards such as pre-vaccination screening, post vaccination observation period and ensuring that all vaccination centres are medically equipped and staffed by qualified medical professionals are in place to mitigate this risk,” HSA said.

The authority added that it is watching closely for reports of myocarditis, which is a heart muscle inflammation, and pericarditis, which is an inflammation around the heart muscle lining, from individuals who received the Nuvaxovid vaccine. To date there have been no such reports.

The Nuvaxovid Covid-19 vaccine uses a long-established protein-based technology that is an alternative to the messenger ribonucleic acid (mRNA) vaccines by Pfizer-BioNTech and Moderna.

Update on other vaccines

In the same report, HSA said gave an update on other Covid-19 vaccines administered here.

As of Aug 31, a total of 15.8 million doses of Covid-19 vaccines have been administrated with the majority (95.9 per cent) of those being mRNA vaccines (Pfizer-BioNTech/Comirnaty, Moderna/Spikevax), followed by inactivated Covid-19 vaccines Sinovac-CoronaVac and Sinopharm (4 per cent) and the Nuvaxvoid vaccine (0.1 per cent).

The reporting rates of "adverse events” and "serious adverse events” for the mRNA vaccines remained rare, said the HSA.

The serious adverse reactions reporting rates for the first and second booster doses were at 0.004 per cent (162 reports) and 0.0005 per cent (two reports), respectively — lower than those for the primary doses at 0.009 per cent (916 reports).

HSA added that there were no new safety findings since its last update.

As for inactivated vaccines, a total of 635,420 doses have been administered here as of Aug 31.

The serious adverse effects reporting rate remained rare at 0.006 per cent (39 reports), said HSA.

As with the case of mRNA vaccines, there were no new safety findings for the inactivated vaccines since the last update in June, it added. — TODAY