Pathogen of the Month, Viruses

Tomato Flu Explainer: What Is It? Is It a New Virus or Not? All You Need to Know

Author Chandana Balasubramanian , 07-Sep-2022

News outlets in India have been talking about a mysterious new illness called the ‘tomato flu’ [1]. While the rest of the world may not have heard about it yet, in the age of information (or misinformation), it’s only a matter of time. So, just as the COVID-19 pandemic seems to be dying down, do we now have a whole new virus on our hands? Here’s all you need to know. 


But first, [spoiler alert]: there is no new virus. There may, however, be a new variant of Coxsackie A16. A commonly-known enterovirus, Coxsackie A16 is one of the main causes of hand, foot, and mouth disease (HFMD) [2]. 

Why the Name ‘Tomato Flu’?


The terms ‘tomato flu’ or ‘tomato fever’ are misleading because tomato flu does not come from tomatoes, and it is not a flu. The condition was simply named so because infected children have large, painful, red blisters that grow to the size of a tomato [3]. To learn more, let’s look at what symptoms are being reported. 


What Are The Symptoms of Tomato Flu?


In August 2022, the Lancet Respiratory Medicine published a letter titled, ‘Tomato flu outbreak in India’. In it, the authors stated, “just as we are dealing with the probable emergence of the fourth wave of COVID-19, a new virus known as tomato flu, or tomato fever, has emerged in India in the state of Kerala in children younger than 5 years.” They also added that the primary symptoms in children with tomato flu are similar to that of chikungunya, with high fever, rashes, and intense joint pain. They note that the blisters are similar to monkeypox rashes in children. Additionally, they speculate if the ‘new virus’ is a variant of hand, foot, and mouth disease [4]. 


Tomato flu symptoms include: 

  • High fever
  • Joint pain
  • Rashes (similar to monkeypox in children) 
  • Painful, red, and large blisters that can even grow to the size of a tomato (hence the name) 
  • Young children may get sores in their mouth which prevent them from swallowing, which may lead to dehydration [4]. 


Who is at Risk of Getting Tomato Flu?


Hand, foot, and mouth disease affects mostly young children and infants but adolescents and adults can get it too [5]. 

Is Tomato Flu Serious?


No serious illness or deaths have been reported due to the tomato flu so far. According to the World Health Organization (WHO), HFMD is mild and self-limiting (can resolve on its own without treatment) in the majority of cases [5]. However, HFMD can have complications with the central nervous system and even death when the disease progresses in severity [6]. 

Most HFMD deaths reported have been due to Enterovirus A71, another enterovirus that causes HFMD. For example, the GIDEON infectious diseases database reports these deaths from HFMD in China: 

  • 1998 to 2007: The case-fatality rate of HFM due to Enterovirus 71 in China was estimated at 1.5% (meta-analysis)
  • 2008 to 2012: The case-fatality rate of HFM due to Enterovirus 71 in China was estimated at 1.8% (meta-analysis) [7]
  • 2008 to 2018: 3,646 fatal cases of HFMD in children below age 5 years were reported – 0.87 per 100,000 in 2011, 0111 per 100,000 in 2018. Enterovirus A71 accounted for 92.07% of deaths [8]

Is Tomato Flu Contagious?

According to infectious disease expert Dr. Stephen Berger, MD, “Tomato flu seems to be contagious and can spread from person to person. However, there is no evidence that mosquitoes or respiratory droplets spread it. Hand, foot, and mouth disease are spread through feces and the fluids in the blisters that appear.” 


How is Tomato Flu Diagnosed?


The Coxsackie A16 enterovirus can be identified through physical evaluation by a qualified medical professional. Throat samples or swabs from blisters can be tested in a lab. 

Does Your Child Have Tomato Flu or Monkeypox?


If your child happens to have unusual rashes, bumps, or blisters, isolate and contact a healthcare provider to learn more. Dr. Berger adds, “It’s important not to panic. The tomato flu, HFMD, and monkeypox are self-limiting diseases. This means, in most cases, people get better on their own without treatment. Supportive treatment can offer relief from symptoms. For example, paracetamol can help control fevers” [9,10]. 

What Do You Do If Your Child Has Tomato Flu?


According to India’s Union Health Ministry guidelines, there is a need to isolate for 5-7 days following the onset of symptoms [11].  


In the End, is The Tomato Flu Just a Case of ‘Potato Potahto’?


It may be too soon to tell whether the tomato flu is just HFMD or a variant of Coxsackie A16. In August 2022, the UK Health Security Agency tested skin lesions from two children with symptoms and discovered a Coxsackie A16 virus infection through viral sequencing [12]. From what we can tell now, even if the tomato flu turns out to be just a case of mistaken identity, the outbreak deserves attention. After all, a disease by any other name is just as painful (paraphrasing Shakespeare).  

The big picture tells us that there is an outbreak (endemic for now) that may spillover to other countries. A 100 young kids are, or have been suffering, from large, red, and extremely painful blisters, high fever, joint pain, and other symptoms [1, 4]. Additionally, with symptoms similar to monkeypox during a global monkeypox outbreak, imagine the stress and social stigma that infected children and their caregivers may experience. While there may be no new virus, the real mystery is why the Coxsackie A16-related symptoms confused physicians across South Asia. After all, HFMD is common and South Asia is no stranger to enterovirus infection outbreaks. 

What we do know for sure is that, in this global age, there is an urgent need for epidemiology at the forefront during point-of-care diagnoses. When pathogens and information can spread like wildfire, clinicians on the frontlines need to have data at their fingertips. Additionally, a robust differential diagnosis and probability engines platform can support clinicians as they evaluate symptoms and decide what tests to administer. 



[1] S. Pitt and The Conversation, “What is tomato flu, the ‘new virus’ found among children in India?,”, 31-Aug-2022. [Online][Accessed: 03-Sep-2022].

[2]  A. M. Guerra, E. Orille, and M. Waseem, “Hand foot and mouth disease,” in StatPearls [Internet], StatPearls Publishing, 2022. 

[3] K. Thiagarajan, “Reports of ‘tomato flu’ outbreak in India are not due to new virus, say doctors,” BMJ, vol. 378, p. o2101, 2022.

[4] V. P. Chavda, K. Patel, and V. Apostolopoulos, “Tomato flu outbreak in India,” Lancet Respir. Med., vol. 0, no. 0, 2022.

[5 ] Hand, foot and mouth disease,” [Online] [Accessed: 03-Sep-2022].

[6] Z. Liu et al., “The burden of hand, foot, and mouth disease among children under different vaccination scenarios in China: a dynamic modelling study,” BMC Infect. Dis., vol. 21, no. 1, p. 650, 2021.

[7] Y. Y. Zhao, H. Jin, X. F. Zhang, and B. Wang, “Case-fatality of hand, foot and mouth disease associated with EV71: a systematic review and meta-analysis,” Epidemiol. Infect., vol. 143, no. 14, pp. 3094–3102, 2015.

[8] Cui J. Z. et al., “Epidemiological characteristics of fatal cases of hand, foot, and mouth disease in children under 5 years old in China, 2008-2018,” Zhonghua Liu Xing Bing Xue Za Zhi, vol. 41, no. 7, pp. 1041–1046, 2020.

[9] CDC, “Learn more about Hand, Foot, and Mouth Disease,” Centers for Disease Control and Prevention, 17-May-2022. [Online] [Accessed: 03-Sep-2022].

[10] CDC, “Monkeypox,” Centers for Disease Control and Prevention, 01-Sep-2022. [Online][Accessed: 03-Sep-2022].

[11] Express News Service, “Centre issues guidelines on Tomato Flu, says not related to SARS-CoV-2, monkeypox, dengue or chikungunya,” The New Indian Express, The New Indian Express, 23-Aug-2022.

[12] J. W. Tang et al., “Kerala tomato flu – A manifestation of hand foot and mouth disease,” Pediatr. Infect. Dis. J., vol. Publish Ahead of Print, p. 10.1097/INF.0000000000003668, 2022.

Chandana Balasubramanian

Chandana Balasubramanian is an experienced healthcare executive who writes on the intersection of healthcare and technology. She is the President of Global Insight Advisory Network, and has a Masters degree in Biomedical Engineering from the University of Wisconsin-Madison, USA.

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