SINGAPORE, June 28 — As of May 31, there have been four reports of "non-serious adverse events" in the two weeks following the roll-out of the Nuvaxovid Covid-19 vaccine in Singapore, the Health Sciences Authority (HSA) said yesterday (June 27).

These events included dizziness, rash, vasculitis (inflammation of blood vessels) and chest pain.

“These are largely consistent with what was reported in the clinical studies and are known adverse effects associated with vaccines,” HSA said in its 12th vaccine safety report, which covers the period from December 30, 2020, to May 31 this year.

Advertisement

A total of 2,792 doses of the Nuvaxovid Covid-19 vaccine have been administered as of May 31 since the rollout of the vaccine on May 18, 2022.

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.

An adverse event for vaccination is any undesirable medical condition that occurs after taking the vaccine and it has to be reported by healthcare providers to HSA. It is classified as serious when the event results in conditions such as hospitalisation, a significant reduction in functioning level, a life-threatening illness or death.

Advertisement

HSA said in its report that it has not received any reports of myocarditis (inflammation of the heart muscle), noting that a small number of cases have been observed from ongoing global clinical trials.

“Although the potential risk of myocarditis with Nuvaxovid Covid-19 vaccine cannot be excluded, the benefits of the vaccine continue to outweigh the risks in the Singapore context,” HSA added.

The authority also gave an update on the other Covid-19 vaccines in use, saying that incidence rates of adverse events of interest with messenger ribonucleic acid (mRNA) vaccines have stabilised, with no new findings since the last update in February.

Adverse events of interests refer to conditions such as anaphylaxis (a life-threatening allergic reaction), myocarditis, pericarditis (inflammation of the heart membrane) and cerebral venous thrombosis (rare type of blood clot that occurs in the veins of the brain).

The incidence rates of adverse events and serious adverse events for the Sinovac-CoronaVac and Sinopharm vaccines have also remained stable and there are no new safety updates, HSA said.

Rare cases of appendicitis linked to mRNA vaccines

A total of 21 cases of appendicitis following Pfizer-BioNTech (Comirnaty) Covid-19 vaccination here have been reported, HSA said in its report.

Appendicitis — inflammation of the appendix — can be caused by various factors such as infections in the digestive tract or blockage of the opening of the appendix, causing it to become sore and swollen.

There have been rare cases of appendicitis following vaccination reported globally, HSA said.

Its analysis had found a small increased incidence of appendicitis occurring within 21 days after the primary vaccination series of the Pfizer-BioNTech (Comirnaty) vaccine, mainly in individuals 12 to 17 years old.

“No increased incidence of appendicitis has been observed with the booster dose of the vaccine,” HSA added.

This is after more than 11 million doses of the Pfizer-BioNTech (Comirnaty) vaccine were administered here.

All 21 patients who had appendicitis were hospitalised and have since been discharged. ― TODAY