What are the different stages of vaccine development?

Nine months into the COVID-19 pandemic, scientists and pharmaceutial companies around the world are racing to develop an effective vaccine against SARS-CoV-2, the coronavirus that causes COVID-19. According to the latest list of the World Health Organization (WHO), at least 200 vaccines are at various stages of development.

According to Russian State media, the first batch of Russia’s vaccine, Sputnik V, entered “civil circulation” on September 24 in capital Moscow. However, its safety and effectiveness is being looked at sceptically because the results of only the phases 1 and 2 of the trials have been published. Earlier, reports emerged that the third stage trials were ongoing in Russia and a few other countries. Phase 3 of clinical trials of the Sputnik V vaccine will begin in India in the coming weeks.

China has about 11 vaccine candidates in various stages of human testing. China has been administering experimental coronavirus vaccines to large numbers of workers deemed to be at high risk of exposure to the virus. They include frontline health workers, public service workers and border officials. A vaccine developed by CanSino Biologists and named Ad5-nCoV was approved for use within the Chinese military as early as June 2020. Four other vaccines are in the final stages of clinical trials. Chinese officials say that the country will be able to roll out a vaccine for public use by November or December. China has promised to provide doses to at least 62 countries.

Among other vaccine contenders that have drawn global attention is the one being developed by the Oxford University in partnership with phaemaceutical company AstraZeneca. Hopes were high when it successfully carried out phases 1 and 2 of the trials. But the final clinical trials had to be briefly put on hold in September after a study participant developed a suspected serious adverse reaction.

COVID-19 vaccines are also being developed by Pfizer and BioNTech in the U.S. and Germany; Johnson and Johnson in the U.S.; Sanofi along with GlaxoSmithKline in the U.K. and Franc; and Novavax in the U.S. Some of these companies have signed deals with multiple countries for trials.

Back home, in India, there are at least eight vaccine candidates under development. The phase 3 clinical trial of ‘Covishield’, being developed by Oxford University and the Serum Institute of India, is underway. Indian candidates, Covaxin, by Bharat Biotech, and ZyCoV-D, by Zydus Cadila, are currently in phase 2 trials.

Experts maintain that even at this speed a vaccine will not be ready before mid-2021.


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What happens when you put water on a candle?

Warm the base of a candle and stick it to the bottom of a small bowl. Pour water into the bowl till the water reaches the rim of the candle. Light the candle. It will burn and the flame will form a crater in the candle.

The base of the flame will sink below the surface level of the water, but the water will be prevented from extinguishing the flame by the thin wall of wax that is left standing all around it.

How does the wall form?

The water takes up so much heat that the outer layer of the candle does not reach melting point. As a result, the wax there cannot evaporate and burn. It remains like a wall around the flame.


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Before cooking an egg, how do you find out if it is fresh or stale?

Immerse the egg in a bowl of water. If the egg lies horizontally on the bottom of the vessel containing the water the egg is probably fresh; if the egg stands on its pointed end, the egg may be several days old.

What is the basis for testing of freshness of eggs in this way?

Eggs contain tiny pores invisible to the naked eye, through which air can enter or leave the egg. The air in the egg is contained in the air cell situated at the broader end of the egg.

Due to the gradual evaporation of water from the egg after it has been laid, the air cell becomes larger as the days pass. This makes the broader end lighter than the rest of the egg, so if an egg that is several days old is placed in water, the broader side will float upward causing the egg to stand on its pointed end.


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What are the great scientific discoveries?

Life is full of problems, and scientists are always trying to find new ways to solve them. There are hundreds of great scientists who have changed our lives for the better,through their discoveries and their inventions. Here are seven of them.


Charles Darwin worked out how animals, such as moths and beetles, can change over many generations to become new species. This process is called evolution.


Ada Lovelace wrote the first published computer program. She also predicted that a computer would be able to make music and images, not just do sums.

Light bulb

Thomas Edison is best known for inventing the first light bulb that could be made in large numbers. He also invented a sound-recorder and a moving-image projector, which helped to start the age of movies.


Issac Newton is said to have discvered how gravity works when he saw an apple fall from a tree. He realized that there must be a similar force that keeps the Earth moving around the Sun.


Marie Curie discovered two substances, called radium and polonium, which give off invisible rays that can pass through materials. She called these rays radioactivity.


Albert Einstein’s theories of relativity, along with his ground-breaking E = mc^2 equation, helped scientists to understand the Universe, and how energy, mass, space, and time are all related.


Alexander Fleming discovered penicillin, which led to the creation of a group of medicines called antibiotics. They kill the bacteria that cause many infections in humans and other animal, and so have saved millions of lives.


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What is the human skeleton made of?

Like all vertebrates, humans have a bony skeleton underneath their skin and muscles. It is a framework to hold up the body, help it move, and protect what is inside. The amazing brain makes humans the cleverest of all the animals. That includes you!


The brain controls the body, sorting out information from the world around you and sending out instructions. It also stores memories.


With each beat, the heart pumps blood around the body, delivering nutrients and oxygen to every part.


Lungs bring air into the body through breathing. This air contains oxygen, which is needed to keep the body alive.


The body needs food to survive. The digestive system breaks food down, keeping the nutrients and getting rid of the waste.

Strong muscles

Muscles are like elastic straps that can stretch or squeeze. Many muscles move the body by pulling on the bones.

Standing tall

Unlike most animals, humans walk upright on two legs. This allows the arms to be used for other activities such as making things.

Body facts

  • Human skeletons contain more than 200 bones. The smallest bone is inside the ear and in only 3 mm (3/25 in) long.

  • The thigh bone is the strongest bone in the body. It is about four times stronger than concrete.

  • A human heart beats more than 100,000 times in a day. That is over 35 million times in a year.

  • In one day, blood travels about 19,000 km (12,000 miles) around the body.


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