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General Studies 3 >> Science & Technology

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1. Context

The Food and Drug Administration (FDA) in the U.S. recently approved the world's first chikungunya vaccine, marking a significant milestone in the fight against this viral infection. Developed by European vaccine manufacturer Valneva, the vaccine, known as Ixchiq, has been deemed a crucial tool for preventing this debilitating disease.

2. About Chikungunya

  • Chikungunya is characterised by severe joint pain and impaired mobility and comes with fever.
  • It is a viral infection (CHIKV) transmitted primarily by the Aedes aegypti and Aedes albopictus mosquitoes. It has been described as "an emerging global health threat."
  • The WHO fact sheet says Chikungunya is prevalent in Africa, Asia, and the Americas.
  • Sporadic outbreaks have been reported in other regions.
  • Since 2004, outbreaks of CHIKV have become more frequent and widespread.
  • This is partly due to viral adaptations allowing the virus to be spread more easily by the Aedes albopictus mosquitoes.

3. Clinical Manifestations of Chikungunya

  • The joint pain is often debilitating and varies in duration. It can last for a few days, but also be prolonged over months.
  • Other symptoms include joint swelling, muscle pain, headache, nausea, fatigue, and rash.
  • While severe symptoms and deaths from chikungunya are rare, they are usually related to other coexisting health problems.
  • It is believed that the numbers are generally underestimated because chikungunya is often misdiagnosed as dengue or zika, as symptoms can seem similar. As of now, there is no cure, only symptomatic relief.
  • This includes analgesics to help with the pain, antipyretics for the fever, rest, and adequate fluids.
  • Prevention includes mosquito control activities, primarily falling under public health outreach and routine civic maintenance.
  • Individuals are also advised to use medicated mosquito nets and ensure that there is no water stagnation in any containers at home in order to prevent the breeding of mosquitoes.
4. Vaccine Composition and Effectiveness
  • Ixchiq is administered as a single dose by injection into the muscle.
  • It contains a live, weakened version of the chikungunya virus and may cause symptoms in the vaccine recipient similar to those experienced by people who have the disease.
  • Its safety was evaluated in two clinical studies conducted in North America.
  • About 3,500 participants, 18 years of age and older, received a dose of the vaccine.
  • The other study included about 1,000 participants receiving a placebo.
  • The most reported side effects by vaccine recipients were headache, fatigue, muscle pain, joint pain, fever, nausea, and tenderness at the injection site.
  • The effectiveness of the vaccine was based on immune response data from a clinical study conducted in the U.S. in individuals 18 years of age and older.
  • In this study, the immune response of 266 participants who received the vaccine was compared to the immune response of 96 participants who received the placebo.
  • The level of antibody evaluated in study participants was based on a level shown to be protective in nonhuman primates that had received blood from people who had been vaccinated.

5. Significance of Vaccine

  • Vaccines are designed to prevent diseases by stimulating the immune system to recognize and combat specific pathogens, such as viruses or bacteria. They help the body develop immunity without causing the disease itself.
  • Vaccines have been instrumental in eradicating or significantly controlling many infectious diseases worldwide. Diseases like smallpox have been completely eradicated, and others, such as polio and measles, have seen drastic reductions in cases due to vaccination efforts.
  • Vaccines protect not only individuals but also communities and populations by establishing herd immunity. When a significant portion of a population is vaccinated against a contagious disease, it becomes more challenging for the disease to spread, thereby protecting even those who aren't vaccinated, such as individuals who cannot receive vaccines for medical reasons.
  • Vaccines help reduce the burden on healthcare systems by preventing illness, hospitalizations, and long-term medical care associated with infectious diseases. This, in turn, saves healthcare costs and resources.
  • In the context of global health security, vaccines play a crucial role in combating infectious diseases that can rapidly spread across borders. They are essential tools in managing pandemics and preventing the emergence of new public health crises
  • By preventing illnesses and their associated complications, vaccines contribute to a better quality of life for individuals and societies. They allow people to live healthier lives, attend school regularly, and contribute more fully to the economy
  • Vaccine development involves significant scientific research and innovation. Advances in vaccine technology have not only improved the efficacy and safety of vaccines but have also paved the way for new methods of disease prevention and treatment. 

6. Types of vaccines

There are many different types of vaccines, but they can be broadly categorized into the following types:

  • Live attenuated vaccines contain a weakened form of the live virus that causes the disease. The weakened virus is not strong enough to cause the disease, but it can stimulate the body's immune system to produce antibodies that can protect against the disease. Examples of live attenuated vaccines include the measles, mumps, and rubella (MMR) vaccine and the varicella vaccine.
  • Inactivated vaccines contain a killed form of the virus or bacteria that causes the disease. The killed virus or bacteria is not able to cause the disease, but it is still able to stimulate the body's immune system to produce antibodies. Examples of inactivated vaccines include the polio vaccine and the hepatitis A vaccine.
  • Subunit vaccines contain only a part of the virus or bacteria that causes the disease, such as a protein or sugar. The subunit is not able to cause the disease, but it is still able to stimulate the body's immune system to produce antibodies. Examples of subunit vaccines include the hepatitis B vaccine and the human papillomavirus (HPV) vaccine.
  • Toxoid vaccines contain the toxin produced by a bacterium, rather than the bacterium itself. The toxin is modified so that it is not able to cause disease, but it is still able to stimulate the body's immune system to produce antibodies that can neutralize the toxin. Examples of toxoid vaccines include the tetanus vaccine and the diphtheria vaccine.
  • mRNA vaccines contain messenger RNA (mRNA) that instructs cells to make a protein. The protein is then recognized by the immune system, which produces antibodies to protect against the disease. Examples of mRNA vaccines include the Pfizer-BioNTech COVID-19 vaccine and the Moderna COVID-19 vaccine.
  • Viral vector vaccines use a modified virus to deliver a gene from another virus or bacterium into human cells. The gene then instructs the cells to make a protein that is recognized by the immune system, which produces antibodies to protect against the disease. Examples of viral vector vaccines include the AstraZeneca COVID-19 vaccine and the Johnson & Johnson COVID-19 vaccine.
  • DNA vaccines contain DNA that instructs cells to make a protein. The protein is then recognized by the immune system, which produces antibodies to protect against the disease. DNA vaccines are still in development, but they have the potential to be a more effective and long-lasting way to protect people from infectious diseases.
For Prelims: chikungunya vaccine, COVID-19 vaccine, Food and Drug Administration, World Health Organization, dengue, Zika, National Centre for Vector Borne Diseases Control, 
For Mains: 
1. Critically analyze the effectiveness of current mosquito control strategies in preventing chikungunya transmission in India. (250 Words)


Previous Year Questions

1. With reference to recent developments regarding ‘Recombinant Vector Vaccines’, consider the following statements: (UPSC 2010)

1. Genetic engineering is applied in the development of these vaccines.
2. Bacteria and viruses are used as vectors.

Which of the statements given above is/are correct?

(a) 1 only      (b) 2 only        (c) Both 1 and 2          (d) Neither 1 nor 2

Answer: C

2. Chikungunya is transmitted by: (MPPEB Group 2  2021) 
A. Aedes mosquitoes       B. Female Anopheles       C. Cockroach         D. Rat
Answer: A
3. In the context of vaccines manufactured to prevent COVID-19 pandemic, consider the following statements: (UPSC 2022) 
1. The Serum Institute of India produced COVID-19 vaccine named Covishield using mRNA platform.
2. Sputnik V vaccine is manufactured using vector based platform.
3. COVAXIN is an inactivated pathogen based vaccine.
Which of the statements given above are correct?
A. 1 and 2 only       B.  2 and 3 only       C.  1 and 3 only       D. 1, 2 and 3
Answer: B
4. Covid-19 is which of the following? (Rajasthan Police Constable 2020) 
A. An under study vaccine for the corona virus.
B. Drug used to treat corona virus.
C. Another name for the corona virus that created the epidemic in 2019.
D. All diseases in 2019.
Answer: C
5. Which of the following facts about Covid - 19 virus is / are wrong? (TNPSC Group 1 2021)
(a) People who have been infected by the virus but do not have symptoms do not spread virus. (b) Reinfection is not possible. 
(c) Anosmia (loss of smell) is a symptom.
(d) Babies do not get infected by Corona virus.
A. (a) and (b) only    B. (a), (b), and (d)    C.  (c) only        D.  (d) only   E. Answer not known Answer: B
6. As per the World Health Organisation (WHO) recommendation of a balanced diet, to avoid unhealthy weight gain, total fat should NOT exceed _______ of total energy intake. (UPSSSC Mandi Inspector 2019) 
A. 20%        B. 30%         C. 10%          D. 40%
Answer: B
7. Dengue is caused by- (MP Police Constable 2022)
A. Bacteria       B. Virus         C.  Fungus         D. Pollution
Answer: B

8. Which of the following diseases can be transmitted from one person to another through tattooing? (2013)

  1. Chikungunya
  2. Hepatitis B

Select the correct answer using the codes given below:

(a) 1 only    (b) 2 and 3 only       (c) 1 and 3 only        (d) 1, 2 and 3

Answer: B

9. Consider the following statements: (UPSC 2017)
1. In tropical regions, Zika virus disease is transmitted by the same mosquito that transmits dengue.
2. Sexual transmission of Zika virus disease is possible.
Which of the statements given above is/are correct?
A. 1 only          B. 2 only          C.  Both 1 and 2             D. Neither 1 nor 2
Answer: C
 Source: The Hindu

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