1) Do COVID-19 and Dengue have any similarities?

The similarities between Dengue and COVID-19 are:

    • Both Dengue and COVID-19 are systemic and viral infections. They both are fatal diseases as both can result in the death of the patient.
    • There is no particular age group for Dengue and COVID-19. Therefore, any person of any age can get infected with Dengue or COVID-19.
    • Patients who already have diabetes, cardiovascular disorders, and kidney disorders are at high risk of Dengue and COVID-19.
    • Reaching out to a healthcare provider as soon as symptoms of either Dengue or COVID-19 are visible is crucial. The disease worsens if the patient takes a long time to visit a physician and does not take any necessary hospital care or steps to bring the condition under control.
    • Differentiating Dengue from COVID-19 based on symptoms can be complicated since both Dengue and COVID-19 show early symptoms like severe fever, abdominal pains, muscle pain, etc.

2) How can we differentiate Dengue from COVID-19?

Dengue and COVID-19 can be differentiated based on:

    • The cause of the disease
      Dengue fever is a vector-borne disease. It is caused by the four serotypes of the dengue virus, namely DENV-1, DENV-2, DENV-3, and DENV-4.
      COVID-19 is a severe respiratory disorder caused by the SARS-COV-2 virus.
    • Transmission
      Dengue fever is a vector-borne viral disease transmitted by the bite of Aedes aegypti or Aedes albopictus mosquito.

      COVID-19 is a respiratory disorder transmitted from one person to another person via respiratory droplets. For example, a person can transmit COVID-19 to someone standing or sitting near them through sneezing, coughing, talking, or shaking hands without proper washing.
    • Likelihood of getting Infected
      People who:
        1. Travel to dengue-endemic regions without proper protection
        2. Do not keep their surroundings clean and remove stagnant water
        3. Wear full sleeve clothes, and
        4. Do not use mosquito nets in dengue-prone areas.

They have a high risk of getting Dengue. A person gets infected with Dengue four times in their lifetime since there are four different serotypes of the dengue virus.
In the case of COVID-19, people who:

        1. Do not maintain social distancing.
        2. Travel to the highly COVID-19 prone area without a proper kit
        3. Do not wear masks
        4. Do not wash their hands before going outside or coming inside the house have a high risk of getting infected with COVID-19.
    • The period of Incubation
      Period of Incubation for Dengue:
        1. Extrinsic Incubation Period: 95% of EIPS are
          a) Between five and 33 days at 25oC
          b) Between two and fifteen days at 30oC
        2. Intrinsic Incubation Period: three to 14 days before the onset of the symptoms.

Period of Incubation for COVID-19:
Incubation Period for the New Coronavirus
On average, symptoms appear in a newly infected person about 5.6 days after contact.

Incubation Period for the Delta Variant:
Delta SARS-CoV-2 variant spreads more quickly and has a shorter incubation period than previous SARS-CoV-2 variants. Delta’s incubation time is approximately four days, compared to 5.6 days for other strains.

    • Signs and Symptoms
      Signs and Symptoms for Dengue:
        1. Myalgia
        2. Pain in the bone or joints
        3. High fever ( around 1040F)
        4. Pain behind the eyes
        5. Severe headache
        6. Skin Rash (observed two to five days after infection)
        7. Swollen lymph glands
        8. Minor hemorrhagic manifestations like purpura, epistaxis, bleeding gums, hematuria.
        9. A positive result of the tourniquet test.

Signs and Symptoms during severe Dengue:

        1. Severe pain in the stomach
        2. Bleeding from the gums and nose
        3. Presence of blood in the urine, stools, or vomit
        4. Difficulty in breathing or rapid breathing
        5. Irritability
        6. Fatigue
        7. Persistent vomiting ( a person will vomit three times or more in 24 hours)

Signs and Symptoms of COVID-19:

        1. Mild, Moderate, or Severe Fever
        2. Dry Cough
        3. Difficulty in breathing
        4. Fatigue
        5. Myalgia
        6. Headache
        7. Loss of taste or smell for a temporary period
        8. Sore Throat
        9. Runny nose
        10. Vomiting
        11. Diarrhea

Emergency medical care is needed if a person with COVID-19 shows the following symptoms:

        1. Restlessness with rapid breathing
        2. The person cannot stay awake
        3. Pneumonia in both the lungs
        4. Septic shock
        5. Pain in the chest
        6. Pale, gray, or blue-colored skin, lips, or nail beds, depending on skin tone
    • Risk Factors
      The risk factors for dengue fever are:
        1. Traveling to or living in the dengue-endemic regions of the world.
        2. Presence of broken cans, earthen pots, old tyres, and other water-holding containers as garbage around the house. Rainwater or water from drainage, when it gets collected in such garbage dumps, they become the breeding place for mosquitoes.
        3. Females are at high risk of getting severe Dengue than males.
        4. High Body Mass Index, Polymorphism in specific genes, and Viral Load are risk factors for severe Dengue.
        5. G6PD deficiency disease in patients is also a high-risk factor for getting severe Dengue.

The risk factors for COVID-19 are:

        1. The risk factor of getting infected with COVID-19 is more likely found in older people who have any severe illness. People above 65 years account for more than 80% of COVID-19 deaths, with people over 45 accounting for more than 95% of COVID-19 deaths.
        2. People and children having the following medical conditions:
          • Cancer
          • Chronic Kidney Disease
          • Lung disorders like COPD, Asthma, cystic fibrosis, interstitial lung disease, and pulmonary hypertension
          • Type 1 & Type 2 Diabetes
          • Alzheimer’s Disease
          • Dementia
          • HIV and other diseases that compromises immunity
          • Hepatic Disorders
          • Overweight and Obese persons
          • Sickle Cell Disease
          • Pregnant women
          • Aggressive smokers
          • Cerebrovascular disease

3) Does a history of Dengue Infection increase the risk of COVID-19?
Dengue and COVID-19 are considered to be syndemic. Syndemic is a term used where two epidemic diseases interact synergically such that one exacerbates the effects of the other. A study carried out on 1285 inhabitants of Mâncio Lima, Brazil, under the principal investigator Marcelo Urbano Ferreira found that people who have a history of Dengue have a two times higher risk of getting symptoms of COVID-19 upon getting infected by the novel coronavirus. The study was published in May in the journal of Clinical Infectious Diseases.

4) Why has Dengue triggered a new challenge in India amid COVID-19?
India has been fighting the outbreak of COVID-19 with many difficulties and losses. Leading healthcare resources such as Hospitals, pathological laboratories, private clinics, nursing homes, healthcare personnel, and the epidemiological monitoring unit have been active in combating the rapid spread of COVID-19 in the country since March 2020. However, while India is doing everything it can to battle COVID-19 outbreaks, from raising awareness to vaccinating every citizen, the nation is in danger of worsening the epidemiological profile of Dengue due to the saturation of health resources and an intense focus only on COVID-19. This has resulted in a setback in coping with, diagnosing, and treating other diseases such as Dengue.
In 2020, India saw a rapid decline in the cases of Dengue. This can be due to any of the two reasons:

    • Lower transmission due to lock down and social distancing
    • A significant difference in the number of dengue cases reported or diagnosed.

As previously stated, this is due to a lack of healthcare resources and under-diagnosis; however, given that the initial symptoms of Dengue are similar to COVID-19, the second reason appears plausible. Both Dengue and COVID-19 are challenging to diagnose because they exhibit nonspecific symptoms such as fever, headache, body pain, abdominal pain, malaise, and so on. As a result, the only way to provide proper treatment is to conduct laboratory tests. However, due to the rapid spread of COVID-19 and the thousands of tests performed daily by laboratory units, diagnosing other diseases such as Dengue becomes a difficult task.

In addition, scientific studies have shown that Dengue and COVID-19 carry the same biochemical and hematological symptoms, such as leukopenia and thrombocytopenia. In addition, serological assays have revealed a false-positive IgM for Dengue in COVID-positive patients.

Thus, due to the oversaturation of healthcare resources, the similarity of the initial symptoms of both Dengue and COVID-19, followed by the difficult task of diagnosing through laboratory tests. Finally, the mortality risk if treatment is delayed in both diseases has presented a difficult task to India’s healthcare authorities amid COVID-19.


    1. How to Know if Your Fever is Due to Dengue or COVID-19? Doctors’ Speak. Accessed at
    2. COVID-19 and dengue fever: similarities and differences. Accessed at
    3. Prior dengue infection considerably increases the risk of symptomatic COVID-19. Accessed at
    4. Amid COVID-19, Dengue triggers new challenge in India. Accessed at
    5. COVID-19 and Dengue: Similarities and Differences. Accessed at
    6. Phadke R, Mohan A, Çavdaroğlu S, Dapke K, Costa ACDS, Riaz MMA, Hashim HT, Essar MY, Ahmad S. Dengue amidst COVID-19 in India: The mystery of plummeting cases. J Med Virol. 2021 Jul;93(7):4120-4121. doi: 10.1002/jmv.26987. Epub 2021 Apr 6. PMID: 33788285; PMCID: PMC8250513.
    7. People with Certain Medical Conditions-COVID-19. Accessed at
    8. Symptoms of COVID-19. Accessed at
    9. Chan, M., & Johansson, M. A. (2012). The incubation periods of Dengue viruses. PloS one, 7(11), e50972. https://doi.org/10.1371/journal.pone.0050972
    10. Gibson CM. Dengue fever risk factors. Accessed at