As Thailand ramped up its Covid-19 vaccine supply, multiple social media posts warned that those who receive a booster shot were at increased risk of developing lymphoma and autoimmune diseases. But the claim is misleading, according to health experts, who said there is no evidence booster increases the risk of developing the diseases.
The claim was published in this Facebook post on October 28, 2021.
It circulated online as Thailand prepared to receive a batch of 560,200 Moderna doses. The Bangkok Post reported on the shipment here.
The post claims that Covid-19 booster shots could increase the risk of lymphoma -- a cancer of the lymphatic system -- and autoimmune disease -- a condition that results in the body's immune system attacking healthy tissues.
The post's lengthy Thai-language caption translates to English in part as: "There is a higher chance that you will get lymphoma instead of Covid-19 from a booster shot. Sent to me from Dr Pirom, Chulalongkorn Hospital.
"There are a lot of warnings from Thai doctors and international reports.
"Now the Covid-19 infection rate is higher, a lot of people are looking for a third booster shot. They are looking for vaccines that stimulate their immunity level.
"But the immunity -- such as [immunoglobulins] or antibodies -- that are created in our body is produced by the activity of lymphocytes. If they are stimulated too much, it may cause lymphoma as well as autoimmune disease (LSE)."
When contacted by AFP, Chulalongkorn University's Faculty of Medicine said it was unable to track the "Dr Pirom" since there is no mention of his full name in the misleading posts. The faculty said they once employed a person called Pirom but he is no longer working at the hospital.
The post goes on to suggest how people should combine different Covid-19 vaccines available in Thailand -- namely AstraZeneca and Sinovac's CoronaVac jab -- to ensure sufficient protection for the disease.
Thailand has also been administering the Pfizer-BionTech jab to young people and healthcare workers after it was approved for emergency use, AFP reported here.
A similar claim was shared here on Facebook and here on Twitter.
However, the claim is misleading.
'No evidence'
There is no evidence that people who receive Covid-19 booster shots are at increased risk of developing lymphoma, experts said.
Dr Thiravat Hemachudha, the Head of the Center for Emerging Infectious Diseases Health Science Center at Thailand's Chulalongkorn University, told AFP: "There is not sufficient evidence to support the claim. However, patients with autoimmune diseases should consult with their doctors before getting a jab."
In response to the misleading posts, Bangkok's Chulalongkorn University released this statement on August 21, 2021.
"The claim that Covid-19 vaccine overly stimulates your immunity level -- which in turn increases your chance of developing lymphoma -- is fake news," it reads in part. "There is no evidence to support it whatsoever -- based on more than one billion doses of Covid-19 jabs administered around the world as well as other vaccines administered.
"People should be vaccinated against Covid-19 immediately. Due to the pandemic, there is a risk of death in case if you get infected before you have been vaccinated."
Dr Tany Thanivayarn, a US-based specialist on pulmonary and critical care medicine, debunked the claim in this video on his official YouTube account on August 8, 2021.
At the four-minute and eight-second mark, he says: "There isn't any medical information that shows lymphoma can be caused by [Covid-19] vaccines."
Booster vaccinations
Thailand is one of a host of countries -- including Israel and the US -- offering booster vaccinations to vulnerable people in a bid to increase protection against Covid-19.
Dr Thiravat said: "The efficacy of Covid-19 vaccines reduces between two to six months. Getting a booster shot with an mRNA vaccine is the best method to protect against Covid-19".
Protection from two doses of the Pfizer and AstraZeneca vaccines wanes within less than six months, according to a study of phone app data published in August, suggesting that booster shots may be needed to ensure prolonged coverage. AFP reported on the study's findings here.
The World Health Organisation has suggested countries should wait until more people are vaccinated around the world before launching booster campaigns.