Viruses Versus Bacteria – Myths and Facts

(Updated 18 Feb 2020 to reflect new information)

The news about the novel coronavirus (now named Covid-19) is everywhere now. We have compiled some quick information about the new virus and what the differences between viruses and bacteria are.

Antibiotics for flu? No!

Facts about bacteria:

  1. Bacteria are single-celled microorganisms. They are small and everywhere—in the air, soil and water, on plants and in animals. Most bacteria, including those in our intestines, are harmless. In fact, we sometimes use bacteria to help us digest food. Probiotic bacteria such as those in your Yakult, Vitagen, or kefir drink are all examples of good bacteria. They help digest food and destroy disease-causing microbes. Fewer than 1 percent of bacteria cause disease in people.
  2. What disease can you get from bacteria? These include sore (strep) throat, tuberculosis, and urinary tract infections (UTI).
  3. Antibiotics can kill or slow the growth of bacteria. They are commonly used to treat more serious bacteria illness. However, bacteria can adapt to antibiotics so overdose may create new strains of bacteria that are resistant to antibiotics. Antibiotics can also kill off healthy bacteria in your body so doctors will not prescribe antibiotics unless necessary.

Facts about viruses

  1. Viruses are even smaller than bacteria and cannot live on their own. A virus must attach itself to a cell and then reprograms the cell to reproduce itself.  It is so small that most can only be seen with powerful electron microscopes. Around 30,000 to 750,000 of them need to be lined up together to form 1 cm. Imagine the whole population of Singapore lined up in just around 10 cm of space – That’s how small they can be!
  2. Viruses that cause diseases are termed as ‘virulent’. Common virus-caused diseases include the common cold, AIDS, cold sores and chickenpox.
  3. Viral infections require either vaccinations to prevent them or antiviral drugs to treat them. Antiviral drugs do not destroy a virus but inhibit its development.
  4. The body is usually capable of recovering on its own without treatment for viral infection as the body has natural immunity to fight off viral infections. Those who are young or old or already have other illnesses or a weakened body immunity however, are more likely to die or unable to cure itself from viral infections.


  1. We need antibiotics for viral infections. Antibiotics are NOT effective against viruses, unless there is also a bacterial infection together with the viral infection. So there is NO need for antibiotics against flu. When antibiotics are prescribed for a viral infection, it is to safeguard against secondary infection by bacteria as the immune system is weakened or there is already a bacterial infection with the viral infection.
  2. The medicine we get for flu will cure the body. Actually, most medicine given for flu like Panadol and cough mixture provide relief from symptoms like pain, fever and cough. The body is the one that usually heals itself.
  3. I only need to take the flu immunization jab once. Wrong! Viruses mutate all the time and each season they are different. Therefore, one needs to take the flu jab for each flu season. But when we have contacted the flu from a virus once, our body will generally be immune against that virus because we have developed the antibodies against it. We fall sick again from flu because we get infected with a different flu virus strain.
Antibodies are Y-shaped molecules, consisting of two heavy chains (H chains) and two light chains (L chains) arranged as shown in the diagram

How do they spread? Both viral and bacterial infections are spread in similar ways:

  1. Coughing and sneezing
  2. Contact with infected people, especially body contact
  3. Contact with contaminated surfaces, food, and water
  4. Contact with infected creatures, including pets, livestock, and insects like fleas and ticks

Why do people confuse between viruses and bacteria?

Viruses and bacteria illnesses usually cause similar symptoms. Some illnesses like pneumonia, meningitis and diarrhoea can be caused by either a virus or a bacterium.

A doctor may be able to tell through a medical history and physical examination or through blood or urine tests or a spinal culture.

What is the coronavirus?

Coronaviruses magnified

Coronaviruses are a family of viruses first detailed in the 1960s. They get their name from the distinctive corona or ‘crown’ of sugary-proteins that come out from the envelope surrounding the virus particle. Most coronaviruses cause just minor illness in mammals and birds but several rare strains have been deadly in animals and humans, including the new Covid-19, SARS and MERS.

ovid-19 s appears to have likely originated from bats and then jumped to a different species and finally onto humans. Because it is new, the human body does not have the antibodies to fight it naturally and there are no antiviral drugs that can fight it yet as well.

Coronaviruses can give rise to a variety of symptoms in different animals. Some strains cause diarrhoea in pigs and in turkeys, and most of the time infections can be compared to a bad cold, causing respiratory problems such as a runny nose and sore throat.

Covid-19 is called a novel coronavirus because it has never been encountered before. Like other coronaviruses, it has come from animals. The initial batch of people infected appeared to have either worked at or frequently shopped in the Huanan seafood wholesale market in Wuhan. Then it got transmitted from human to human. It is important to note that viruses can jump species from anywhere in the world, such as MERS from camels to humans in the middle east and Swine flu (H1N1) from pigs to humans in the Americas.

This virus can cause pneumonia (inflammation of the lungs). Those ill typically suffer coughs, fever and breathing difficulties. In severe cases there can be organ failure. Antibiotics are of no use. The antiviral drugs we have against flu will not work because this is a new virus. Patients may get support for their lungs and other organs as well as fluids. Recovery will depend on the strength of their immune system. As with most who catch flu, many of those who have died are known to have been already in poor health.

What can one do against Covid-19?

As no cure has yet to be found, the general advice is to avoid catching the virus by maintaining good personal hygiene and avoiding crowds, and to develop stronger body immunity with good rest, lots of water and vitamin C. Wash your hands with soap frequently or use sanitizer if there is no running water nearby. The encouraging thing is that scientists globally have been sharing data and research findings openly in the rapid race to find a cure. The world has seen deadlier virus attacks such as the 1918 Spanish Flu that killed over 50 million people and yet recovered, so there is optimism that we will once again ride this one out.

Daily Vitamin C for teachers at our Kids Mansion Childcare during this Covid-19 period to help build immunity

Children at Kids Mansion Childcare with self-made sanitizers to protect themselves and to give to other children at the centre.
Ingredients for home-made sanitizer. Alcohol should be at 70% or higher to be effective against viruses and bacteria.

Meanwhile, do stay healthy!




  1. Viruses are smaller than bacteria – True or False?
  2. Antibiotics can fight off viruses – True or False?
  3. We need good body immunity to fight off viruses already in our body – True or False?

Answers: True, False, True

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