SINGAPORE, June 15 — The risk of medical complications from Covid-19 continues to “far outweigh” that from getting the vaccines, such as heart conditions associated with the after-effects, three independent medical organisations said in a joint statement yesterday (June 14).

The Chapter of Cardiologists at the College of Physicians, the Academy of Medicine and the Singapore Cardiac Society said that they continue to recommend Covid-19 vaccination for eligible patients and will continue to “monitor the situation closely and provide professional guidance accordingly”. 

“Covid-19 vaccination greatly reduces the risk of infection and its serious complications in the majority of individuals, and helps the population achieve herd immunity,” they added.                             

Singapore has approved two vaccines for use here from pharmaceutical firms Pfizer-BioNTech and Moderna, which are the vaccines the three organisations refer to in their statement.

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These vaccines use the new messenger ribonucleic acid (mRNA) technology to “instruct” human cells to make a spike protein that triggers an immune system response against the coronavirus. The spike protein is what viruses use to enter human cells and cause infection.

This is different from the traditional approach where a weakened or inactivated virus with its whole spike protein is used in vaccines to produce antibodies.

Last Friday, the Ministry of Health (MoH) said in a news release that its expert committee for Covid-19 vaccination has advised “adolescents and younger men” to avoid strenuous physical activity for a week after their second dose of the mRNA vaccines as a precaution against a “small risk” of heart inflammation. 

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They should also seek medical attention promptly if they develop chest pain, shortness of breath or abnormal heartbeats.

In Singapore, as of June 7, the Health Sciences Authority (HSA) has reported four men aged 18 to 30 having myocarditis or pericarditis after they received their second jab.

Another two cases involved a man and a woman who are both above 40 years old.

These are inflammatory conditions affecting the heart muscles (myocarditis) and the lining covering the heart (pericarditis).

The three medical organisations noted in their statement that various reports suggest that Covid-19 is associated with both myocarditis and pericarditis, adding that “published rates vary widely”. 

In the largest and most complete of these studies, all patients — all young competitive athletes — who were infected by the coronavirus later underwent cardiac MRI scans, they added.

The study showed that the incidence of myocarditis was 2.3 per cent (ranging from 0 to 7.6 per cent at different institutions), the equivalent of 2,300 for every 100,000 patients infected.

“The data so far is only available for the mRNA vaccines produced by Pfizer-BioNTech and Moderna.

“Initial reports from Israel and the United States suggest a small risk of myocarditis and pericarditis associated with the second dose of the mRNA Covid-19 vaccines.

“Our own Singapore data is too small to be definitive,” the organisations said.

“Nonetheless, preliminary estimates from the US suggest that the overall risk from the second dose of the mRNA vaccines is about 1.6 cases per 100,000 doses, with risk primarily in males under the age of 30.”

HSA has said that the two cases in Singapore of those above 40 years of age “is within the baseline incidence rate”, while the four involving the men aged 18 to 30 “is at the upper end of the expected range for this age group, based on background incidence rates”.

The three organisations added yesterday that people who develop chest discomfort, breathlessness or palpitations after Covid-19 vaccination should seek urgent medical attention.

“After vaccination, and especially after the second dose, strenuous activity should be avoided for one week.” ― TODAY