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Worried about mercury in vaccines? Here's the science behind 'thimerosal'

Worried about mercury in vaccines? Here's the science behind 'thimerosal'

Ever heard of a mercury-based compound in your vaccine? It's called 'thimerosal' — a preservative that keeps multi-dose vials free from bacterial or fungal contamination. Introduced in the 1930s, it contains a form of mercury called 'ethylmercury', which is different from 'methylmercury' which is the toxic type found in certain fish and industrial waste. The two are often confused by people, although they behave very differently in the body.
While thimerosal was once common in childhood vaccines globally, many countries, including the US, began phasing it out around the early 2000s due to rising public concern over mercury exposure, despite no strong evidence of harm. However, certain India's vaccines, especially multi-dose ones, are believed to contain thimerosal.
Why is thimerosal in the news?
The debate over thimerosal surfaced after some public figures made controversial claims linking mercury in vaccines to autism.
At the first meeting of US Health and Human Services Secretary Robert F Kennedy Jr's special committee on vaccines, the panel voted to stop recommending flu vaccines that contain thimerosal. Public health experts warn that this action could undermine trust and spread confusion about vaccine safety.
Moreover, several studies that once claimed a link between thimerosal and autism have since been retracted or discredited.
Does Thimerosal cause autism?
According to a large body of international research, there is no credible evidence that thimerosal causes autism.
In 2004, the US Institute of Medicine reviewed over 200 scientific studies and found no link between thimerosal in vaccines and autism. Later reviews by the CDC (Centers for Disease Control and Prevention) and FDA (Food and Drug Administration) also found no evidence that thimerosal causes autism or developmental delays.
'Thimerosal, an ethyl mercury compound, preserves multi-dose vaccines by inhibiting microbial growth after repeated vial entry. Clinically, it reduces contamination risk in mass immunisation. Decades of surveillance and evidence show no link to autism or serious toxicity at approved doses. In fact, autism rates did not decrease after thimerosal was removed from vaccines, which supports that the vaccines do not increase the risk of autism,' said Dr Deepak Ugra, paediatrician at Lilavati Hospital, Mumbai.
Is thimerosal still used in Indian vaccines?
Many of India's vaccines, particularly those supplied in multi-dose formats, are believed to contain thimerosal.
Dr Ugra explained, 'Thimerosal remains in use within India's routine immunisation programme, especially in multi-dose vials of vaccines like DTP and Hepatitis B. It serves as an antimicrobial preservative. While single-dose, thimerosal-free alternatives are available, their broader rollout is constrained by cost, infrastructure, and supply-chain limitations in public health settings. However, in the private sector only single-dose, preservative-free vaccines are used.'
Is thimerosal safe for children?
Thimerosal breaks down into ethylmercury, which is eliminated from the body quickly and does not accumulate in the body. This sets it apart from methylmercury, which can be toxic in high amounts.
'Parents should not be concerned about mercury in vaccines. Ethyl mercury, one of the metabolites of thimerosal, is excreted quickly and does not have the neurotoxic properties of methylmercury. While mild reactions at the injection site such as redness, swelling, or tenderness, and rarely, contact hypersensitivity may be seen, serious adverse events are extremely rare,' said Dr Ugra.
While thimerosal remains a topic of public interest, current scientific evidence does not support claims linking it to autism. For parents in India, the key lies in staying informed through verified medical sources and consulting paediatricians for vaccine safety.
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7 Indian-origin scientists in the US: Where they studied and how it shaped their careers
7 Indian-origin scientists in the US: Where they studied and how it shaped their careers

Time of India

time4 hours ago

  • Time of India

7 Indian-origin scientists in the US: Where they studied and how it shaped their careers

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Doctor claims threading raises hepatitis risk: ‘Eyebrows banwane gayi thi lekin liver fail karwake aagayi'; internal medicine expert weighs in
Doctor claims threading raises hepatitis risk: ‘Eyebrows banwane gayi thi lekin liver fail karwake aagayi'; internal medicine expert weighs in

Indian Express

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Doctor claims threading raises hepatitis risk: ‘Eyebrows banwane gayi thi lekin liver fail karwake aagayi'; internal medicine expert weighs in

In a video going viral on social media, MBBS Dr Aditij Dhamija can be seen saying that routine visits to neighbourhood parlours to get eyebrows shaped can expose one to 'liver failure risk' owing to hepatitis concern, as it happened in the case of a 28-year-old woman. 'Eyebrows banwane gayi thi lekin liver fail karwake aagayi. 28 saal ki mahila. (She went to get her eyebrows threaded, came back with liver failure). She came to the hospital with fatigue, nausea, and yellow eyes. Tests revealed her liver was giving up — not because of alcohol or medicines — but due to a beauty parlour visit gone wrong. This happened because reused threading material caused micro-cuts, through which Hepatitis B or C viruses entered her bloodstream,' said Dr Dhamija in an Instagram post. While it was unclear whether he treated the patient, his claim raises serious concerns about liver health. We reached out to an expert to understand the link between threading and liver health. Threading is a popular beauty treatment, most commonly for eyebrow shaping or facial hair removal. It is often considered quick, easy, and harmless. So, can it cause liver failure? Dr Amit Saraf, director, internal medicine, Jupiter Hospital, Thane, said threading itself does not cause liver failure, but can establish a risk for hepatitis B and C infections if not done under hygienic conditions. 'Hepatitis B and C are blood-borne viruses that are transferred via infected blood. If you get a small cut or abrasion from the threading, this could act as an entry point for infected blood. The thread, hands, or implements that are used could all pass on the virus, since we do not know if the hands or the thread are contaminated,' said Dr Saraf. Over time, once you have an untreated hepatitis infection, it could progressively damage the liver severely, and in some instances, lead to cirrhosis or liver failure. 'In summary, threading in itself is not dangerous to the liver, but can be risky depending upon the practices that are hygienic,' said Dr Saraf. A post shared by Dr. Aditij Dhamija | Health Educator | MBBS (@drdhamija) What should you note? Always ensure threading takes place in a clean, professional setting. 'Employing a new, disposable thread, washing hands, and sterilising the area before and after the process are simple but fundamental measures. It's also wise to refrain from threading in case of any cuts or active skin infection within the area,' said Dr Saraf. Individuals who get regular threading treatments done must be careful of the possible risks and must go to trained therapists who maintain very proper hygienic standards. DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.

As India's retractions surge, NIRF rankings only now begin penalising tainted research
As India's retractions surge, NIRF rankings only now begin penalising tainted research

The Hindu

time6 hours ago

  • The Hindu

As India's retractions surge, NIRF rankings only now begin penalising tainted research

Between 2004 and 2020, five research papers published by Zillur Rahman on various management topics, such as corporate social responsibility, self-service banking technologies, and service delivery options, were retracted. Yet, he served as the dean and professor of management studies at IIT Roorkee till May 2025. As per data from the Retraction Watch – a non‑profit scientific watchdog that reports retractions of academic papers from across the globe – the former dean's papers were retracted for various reasons, such as plagiarism, duplication, and concerns about data. 'When I reported about Mr. Rahman's retractions to IIT Roorkee on their LinkedIn page, they asked me to provide the list of retractions, and I did. Months later, when I followed up, they asked me to reach out via email. I did not pursue the matter further,' said Achal Agarwal, founder of India Research Watchdog, a not-for-profit that flags research misconduct in Indian academia. The Hindu reached out to Mr. Rahman and the IIT Roorkee's management. There has been no response. India is ranked third with the most number of retractions, only behind the U.S. and China, as per data from Post Pub, a platform that helps visualise country-wise statistics of retractions. Post-Pub data shows that India had a retraction rate (number of retractions for every 1,000 papers submitted) of 1.5 in 2012, which increased steeply to 3.5 in 2022. 'The U.S. has a very large science budget, so it's expected to see a higher number of retractions. China is aiming to become the global leader in research, which makes publishing a top priority. In India, the competition is intense, especially among Ph.D. aspirants and Master's students aiming for doctoral programs,' said John (name changed on request), a sleuth who flags frauds on Twitter. The need for legislation Ever since research papers became a parameter in the National Institutional Ranking Framework (NIRF), private universities have been churning out more research papers — albeit with a focus on quality. That's exactly why there are more papers and more retractions from private universities in the past ten years, as per data from Cornell University. The problem is twofold: the lack of stringent laws to curb scientific corruption and protect sleuths, and the negligence of educational institutions that foster impunity among researchers. In India, in the absence of legislation, the onus to prevent fraud is only on the institutions. However, sleuths say that most universities are mum – firing an academician over research fraud just doesn't happen in India, just as in other countries. 'As long as there is no good legislation to actually sue some of these frauds, nothing will happen. The legislation should have the norms to sue the frauds not just for the fake paper, but also for using government funding to create such a paper. It is a waste of public funding,' said John. The U.K. Research Integrity Office (UKRIO), established in 2006, is an independent charitable body that offers expert advice on research integrity and provides templates for misconduct investigations. Denmark's Act on Research Misconduct, enacted in 2017, assigns severe cases related to fabrication, falsification, and plagiarism to the Danish Board on Research Misconduct for investigation. 'In India, there is a need to have an autonomous, empowered body to look into the complaints. Currently, the complaints go to the respective body governing the institute, such as the Department of Science and Technology or the University Grants Commission (UGC). They don't take these complaints seriously,' said Ms. Agarwal. India Research Watch receives around 10 messages every day from whistleblowers across the country. The nuances of cheating Every retracted paper doesn't indicate fraud; sometimes researchers identify unintentional mistakes such as calculation errors, experimental flaws, or inaccurate data analysis, and withdraw the papers themselves. With the rise of sleuths and watchdog organisations, academicians have grown savvier, learning how to cover their tracks and evade detection. 'It is very difficult to catch smart frauds – those who don't blindly use Artificial Intelligence texts and those who don't just copy-paste texts and images,' Mr. John said. 'We check for tortured phrases, image overlaps, image fakery, statistically improbable data, and methodologies in an academic paper to find out its authenticity. However, the smart frauds have evolved – they plug all these gaps to get better with fraud,' Mr. John added. As it has been established that not all universities punish researchers with retractions, the ball seems to be in the court of publishers. Publishers such as Frontiers rely on AI to check the research papers, but a statement from the publisher says there have been cases of fraud even after the deployment of AI. Frontier's Artificial Intelligence Review Assistant (AIRA) was launched in 2018 and now includes over 50 verifications of submitted manuscripts. On July 29, the communications team of Frontier put out a notice that said, 'Frontier's Research Integrity Auditing team has uncovered a network of authors and editors who conducted peer review with undisclosed conflicts of interest and who have engaged in citation manipulation. The unethical actions of this network have been confirmed in 122 articles published in Frontiers, across five journals, and have led to their retraction.' Beyond plagiarism Ever since the colonial era, it has been mandatory for Indian researchers to send their theses to two foreign evaluators — a practice that began when British academics were the default choice. 'Rather than sending the papers to reputed universities in countries such as Germany, Australia, or the U.S., the lower-quality ones are often sent to universities in Malaysia or Thailand,' said Prof. V. Ramachandran of Anna University. He pointed to another nuance that is common in India's academic system — a nexus between guides, students, and examiners. 'The guides propose a list of examiners to the university — a list that students are aware of. These examiners are often acquaintances of the guide or the student,' Mr. Ramachandran explained, suggesting that universities should independently constitute evaluation panels. 'The examiners must be random and unknown to the student or the guide, and they should be from well-established institutions,' he said. In private universities, academicians are often pressured to publish research papers without adequate funding support. 'At institutions such as mine, faculty are expected to begin research with just ₹1–2 lakh — and that's considered a luxury. In many private universities, researchers are made to start with zero funding,' said a professor from a private university in Tamil Nadu, speaking on condition of anonymity. 'Research output is a key metric in the NIRF rankings, and students look at these rankings while choosing colleges. It's all tied to a profit-making model,' the professor said. Besides fraud, another issue plaguing research is the rise in publications in dubious journals. 'High-standard journals follow tough peer review processes, demand original data and sound science, and are mostly read and cited by reputed researchers across the world. On the other hand, low-standard journals have become dumping grounds for unethical research. Since good scientists don't read these journals, the fraud often goes unnoticed — and most of it never even gets retracted,' the professor from VIT added. Beyond elite institutions, the crisis of research quality runs deeper in smaller universities and colleges, particularly those funded by state governments. 'In Tier 2 and Tier 3 institutions — especially state universities — the drop in research quality isn't linear, it's exponential. Many are publishing in predatory venues. This is far more common in State universities, and that's where serious streamlining is needed,' said a senior academic from IISC Bangalore, seeking anonymity. 'Instead of counting papers, we should assess them on the impact of their teaching.' A long way to go Starting this year, the NIRF will begin assigning negative scores to higher educational institutions for research papers that have been retracted in the past three calendar years, along with any citations those papers had accumulated. While experts see this as a welcome step, many believe the journey toward ensuring research integrity in India remains long. 'At BITS Pilani, we are setting up a Research Integrity Office to proactively educate and sensitise our research community,' said Professor V. Ramgopal Rao, Group Vice Chancellor of BITS Pilani. 'With over 500 new Ph.D. students joining us each year, we see it as our responsibility to train both faculty and students on best practices in research, responsible experimentation, and academic ethics.' Professor Rao, who has been consistently vocal on the need to tackle research fraud, has advocated for the creation of oversight mechanisms both at the institutional and national levels. 'The UGC is fundamentally a grants commission. It neither has the mandate nor the necessary structures to investigate or act on cases of research misconduct. Even if the UGC withholds funding, such activities may continue unchecked,' he observed. The Government of India has introduced a bill in Parliament to set up the Higher Education Commission of India (HECI), which will serve as a single regulator replacing bodies like the UGC and AICTE. Commenting on this, Prof. Rao said, 'The proposed HECI will have the authority to impose penalties on institutions and even recommend their closure in extreme cases. However, since education is a concurrent subject under the Constitution, the Centre cannot act unilaterally. Cooperation from State governments is essential, and that makes the road to implementation long and uncertain.' Drawing a comparison with global practices, he added, 'In the U.S. and Europe, research fraud is treated with the seriousness it deserves. Academicians found guilty can lose their jobs. In India, unfortunately, we have seen cases where even vice-chancellors have been implicated in academic misconduct. When leadership itself is compromised, enforcing standards across the system becomes a much bigger challenge.' (Laasya is an Independent Journalist with bylines published in BBC, Thomson Reuters and Mongabay India among a dozen others. One day she is tracking climate finance; the next, she's decoding education reforms, dissecting caste realities or tracing wildlife in forgotten forests.)

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