Singapore
By Jalelah Abu Baker 13 Apr 2021 08:33AM (Updated: 13 Apr 2021 08:40AM )
SINGAPORE: The sole dormitory COVID-19 case in Singapore on Sunday (Apr 11) had completed the full COVID-19 vaccination regimen – a "reminder" that it is possible for vaccinated individuals to get infected, said the Ministry of Health (MOH).
The 23-year-old Indian national, who is a work permit holder, received his first dose of a COVID-19 vaccine on Jan 25 and the second dose on Feb 17.
He was detected when he was tested on Apr 7 as part of rostered routine testing. The man's pooled rostered routine testing result came back positive for COVID-19 on Apr 8 and he was immediately isolated, said MOH. An individual test on Apr 9 also came back positive the following day. He was asymptomatic.
The man's earlier tests from the rostered routine testing - the last being on Mar 24 - were all negative for COVID-19.
The Health Ministry said that the case is a “reminder that it is possible for vaccinated individuals to get infected”.
“But the vaccine is effective in preventing symptomatic disease for the vast majority of those vaccinated,” MOH added.
CNA spoke to infectious diseases experts about getting infected after vaccination. Here is what you should know:
Question: What are the chances of getting COVID-19 after vaccination?
“Although the currently approved mRNA vaccines are very effective, we must remember that prevention of symptomatic COVID-19 occurred for approximately 94 to 95 per cent of participants in the clinical trials,” said Associate Professor Hsu Li Yang, Infectious Diseases Programme Leader at the National University of Singapore’s Saw Swee Hock School of Public Health.
The Pfizer-BioNTech and Moderna COVID-19 vaccines – both used in Singapore – are mRNA vaccines.
Assoc Prof Hsu noted that the “real world” experience in the United States and Israel shows that the vaccine efficacy was less than 90 per cent.
FILE PHOTO: A medical worker prepares to dilute a vial of Pfizer-BioNTech vaccine at a coronavirus disease (COVID-19) vaccination center in Singapore March 8, 2021. REUTERS/Edgar Su/File Photo
“What this means is that one in 20 persons on average would still develop COVID-19 if exposed to the virus,” he said.
He added that the chances in Singapore “are very low simply because there is minimal spread of COVID-19 in the community”.
“As an illustration, there has only been one reported infection post-vaccination in our dormitory migrant worker community so far despite regular testing, whereas a significant proportion has already been vaccinated,” he said.
Senior consultant in the Division of Infectious Disease at the National University Hospital Dale Fisher said there is “hardly any chance of getting COVID-19 in Singapore ... especially if you are vaccinated”.
“This is because of the social measures still in place and the fact that we currently have good control. It doesn’t have to be this way and this why the measures will likely be removed only gradually and slowly as vaccination rates pick up,” Dr Fisher said.
MOH said on Sunday "we cannot afford to let our guard down".
"Our existing key enablers – safe management measures, testing, and contact tracing – continue to be necessary and effective in helping us to mitigate spread and keep community transmission low," the Health Ministry added.
President of the Asia Pacific Society of Clinical Microbiology and Infection Paul Tambyah said the chances of infection after vaccination depends on the prevalence of the disease.
He gave the example of the “pivotal” Pfizer-BioNTech study conducted in the United States, Europe, South America and South Africa, where nine cases of COVID-19 at least seven days after the second dose were observed among 19,965 vaccine recipients and 169 among 20,172 placebo recipients.
“Bottom line is that it is rare to get the disease after vaccination but not impossible,” said Professor Tambyah.
Question: Why do people get infected with COVID-19 after completing vaccination?
This happens because the strength of the immune response varies across individuals after vaccination, Assoc Prof Hsu said.
A healthcare worker at National Centre for Infectious Diseases prepares to administer one of the first doses of the COVID-19 vaccine in Singapore on Dec 30, 2020.
“For those whose immune systems are compromised, and even for some ... that have otherwise normal immune systems, an adequate immune response that would prevent infection might not develop after exposure to the virus, resulting in infection,” he said.
The mRNA vaccines teach cells how to make at least a piece of a protein that triggers an immune response inside the bodies of those who are vaccinated.
Dr Fisher added that the vaccine is not 100 per cent effective. If it is 90 per cent effective, 10 per cent are still vulnerable, he said.
“This is fully expected. The World Health Organization initially set a target of at least 50 per cent efficacy,” he said.
If a person falls sick after vaccination, it is “very, very acceptable, very expected because of vaccine failures”, said Dr Leong Hoe Nam, infectious diseases expert from Mount Elizabeth Novena Hospital.
Question: Is it a cause of concern if someone who has completed their vaccination gets COVID-19?
This depends on a few factors, said Prof Tambyah. If the person gets severe COVID-19, then it would be a “good idea” to check the lot number or batch of the vaccine to make sure that there was no cold chain break during transport or defect in the manufacture of that particular batch of vaccine, he said.
“That has happened in the past with a number of vaccines. If the disease is mild or the person is asymptomatic, I would not be particularly concerned unless there were more than one case – in which case I would definitely investigate the batch of vaccines used,” he said.
Dr Fisher said that it is “not at all (cause for concern) if numbers are low”.
“If we see large numbers getting infected, especially if there are severe cases, then we would have to consider vaccine failure either because it has worn off or it is ineffective against variants, current or future. Currently the vaccines are still very effective,” he said.
Question: How does vaccination help then?
“The vaccine has converted a life-threatening illness to a moderate illness, moderate illness to mild illness and mild illness to asymptomatic illness, which is great, because you effectively control hospitalisations, you prevent them (hospitalisations),” Dr Leong said.
“If you think about it, no one dies of it, almost everybody is asymptomatic, then we have converted the disease from a bad critical illness to that of a mild cold,” he added.
A person who has not been vaccinated will have more severe symptoms, while a person who has been vaccinated will have much milder symptoms, he added.
However, Dr Fisher cautioned that while the disease is mild in vaccinated people, they would still be infective and therefore a risk to those who are not vaccinated.
Dr Hsu said that vaccination is “still the most effective way of preventing infection, not just in the individual, but also at a population level”. Vaccination goes hand in hand with other non-pharmaceutical interventions like safe distancing, he added.
“There are millions of people worldwide who have been vaccinated (against COVID-19) but those who have been infected post-vaccination number in the low thousands at most. That is pretty good,” he said.
Download our app or subscribe to our Telegram channel for the latest updates on the coronavirus outbreak: https://cna.asia/telegram
Source: CNA/ja
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FAQ: What you should know about getting infected after COVID-19 vaccination
A healthcare worker at National Centre for Infectious Diseases receives one of the first doses of the COVID-19 vaccine in Singapore on Dec 30, 2020.By Jalelah Abu Baker 13 Apr 2021 08:33AM (Updated: 13 Apr 2021 08:40AM )
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SINGAPORE: The sole dormitory COVID-19 case in Singapore on Sunday (Apr 11) had completed the full COVID-19 vaccination regimen – a "reminder" that it is possible for vaccinated individuals to get infected, said the Ministry of Health (MOH).
The 23-year-old Indian national, who is a work permit holder, received his first dose of a COVID-19 vaccine on Jan 25 and the second dose on Feb 17.
He was detected when he was tested on Apr 7 as part of rostered routine testing. The man's pooled rostered routine testing result came back positive for COVID-19 on Apr 8 and he was immediately isolated, said MOH. An individual test on Apr 9 also came back positive the following day. He was asymptomatic.
The man's earlier tests from the rostered routine testing - the last being on Mar 24 - were all negative for COVID-19.
READ: Migrant worker who tested positive for COVID-19 completed vaccination
The Health Ministry said that the case is a “reminder that it is possible for vaccinated individuals to get infected”.
“But the vaccine is effective in preventing symptomatic disease for the vast majority of those vaccinated,” MOH added.
CNA spoke to infectious diseases experts about getting infected after vaccination. Here is what you should know:
Question: What are the chances of getting COVID-19 after vaccination?
“Although the currently approved mRNA vaccines are very effective, we must remember that prevention of symptomatic COVID-19 occurred for approximately 94 to 95 per cent of participants in the clinical trials,” said Associate Professor Hsu Li Yang, Infectious Diseases Programme Leader at the National University of Singapore’s Saw Swee Hock School of Public Health.
The Pfizer-BioNTech and Moderna COVID-19 vaccines – both used in Singapore – are mRNA vaccines.
READ: Moderna's COVID-19 vaccine authorised for use in Singapore
Assoc Prof Hsu noted that the “real world” experience in the United States and Israel shows that the vaccine efficacy was less than 90 per cent.
FILE PHOTO: A medical worker prepares to dilute a vial of Pfizer-BioNTech vaccine at a coronavirus disease (COVID-19) vaccination center in Singapore March 8, 2021. REUTERS/Edgar Su/File Photo
“What this means is that one in 20 persons on average would still develop COVID-19 if exposed to the virus,” he said.
He added that the chances in Singapore “are very low simply because there is minimal spread of COVID-19 in the community”.
“As an illustration, there has only been one reported infection post-vaccination in our dormitory migrant worker community so far despite regular testing, whereas a significant proportion has already been vaccinated,” he said.
Senior consultant in the Division of Infectious Disease at the National University Hospital Dale Fisher said there is “hardly any chance of getting COVID-19 in Singapore ... especially if you are vaccinated”.
“This is because of the social measures still in place and the fact that we currently have good control. It doesn’t have to be this way and this why the measures will likely be removed only gradually and slowly as vaccination rates pick up,” Dr Fisher said.
MOH said on Sunday "we cannot afford to let our guard down".
"Our existing key enablers – safe management measures, testing, and contact tracing – continue to be necessary and effective in helping us to mitigate spread and keep community transmission low," the Health Ministry added.
President of the Asia Pacific Society of Clinical Microbiology and Infection Paul Tambyah said the chances of infection after vaccination depends on the prevalence of the disease.
He gave the example of the “pivotal” Pfizer-BioNTech study conducted in the United States, Europe, South America and South Africa, where nine cases of COVID-19 at least seven days after the second dose were observed among 19,965 vaccine recipients and 169 among 20,172 placebo recipients.
“Bottom line is that it is rare to get the disease after vaccination but not impossible,” said Professor Tambyah.
Question: Why do people get infected with COVID-19 after completing vaccination?
This happens because the strength of the immune response varies across individuals after vaccination, Assoc Prof Hsu said.
A healthcare worker at National Centre for Infectious Diseases prepares to administer one of the first doses of the COVID-19 vaccine in Singapore on Dec 30, 2020.
“For those whose immune systems are compromised, and even for some ... that have otherwise normal immune systems, an adequate immune response that would prevent infection might not develop after exposure to the virus, resulting in infection,” he said.
The mRNA vaccines teach cells how to make at least a piece of a protein that triggers an immune response inside the bodies of those who are vaccinated.
Dr Fisher added that the vaccine is not 100 per cent effective. If it is 90 per cent effective, 10 per cent are still vulnerable, he said.
“This is fully expected. The World Health Organization initially set a target of at least 50 per cent efficacy,” he said.
If a person falls sick after vaccination, it is “very, very acceptable, very expected because of vaccine failures”, said Dr Leong Hoe Nam, infectious diseases expert from Mount Elizabeth Novena Hospital.
Question: Is it a cause of concern if someone who has completed their vaccination gets COVID-19?
This depends on a few factors, said Prof Tambyah. If the person gets severe COVID-19, then it would be a “good idea” to check the lot number or batch of the vaccine to make sure that there was no cold chain break during transport or defect in the manufacture of that particular batch of vaccine, he said.
“That has happened in the past with a number of vaccines. If the disease is mild or the person is asymptomatic, I would not be particularly concerned unless there were more than one case – in which case I would definitely investigate the batch of vaccines used,” he said.
Dr Fisher said that it is “not at all (cause for concern) if numbers are low”.
“If we see large numbers getting infected, especially if there are severe cases, then we would have to consider vaccine failure either because it has worn off or it is ineffective against variants, current or future. Currently the vaccines are still very effective,” he said.
READ: Commentary: ‘Variant-proof’ COVID-19 vaccine key to a pandemic exit
Question: How does vaccination help then?
“The vaccine has converted a life-threatening illness to a moderate illness, moderate illness to mild illness and mild illness to asymptomatic illness, which is great, because you effectively control hospitalisations, you prevent them (hospitalisations),” Dr Leong said.
“If you think about it, no one dies of it, almost everybody is asymptomatic, then we have converted the disease from a bad critical illness to that of a mild cold,” he added.
A person who has not been vaccinated will have more severe symptoms, while a person who has been vaccinated will have much milder symptoms, he added.
However, Dr Fisher cautioned that while the disease is mild in vaccinated people, they would still be infective and therefore a risk to those who are not vaccinated.
Dr Hsu said that vaccination is “still the most effective way of preventing infection, not just in the individual, but also at a population level”. Vaccination goes hand in hand with other non-pharmaceutical interventions like safe distancing, he added.
“There are millions of people worldwide who have been vaccinated (against COVID-19) but those who have been infected post-vaccination number in the low thousands at most. That is pretty good,” he said.
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Download our app or subscribe to our Telegram channel for the latest updates on the coronavirus outbreak: https://cna.asia/telegram
Source: CNA/ja
Continue reading...