21st July 2020
Musings.......
It was with a kind of satisfaction that I had gotten to sleep yesterday night. The reason was of course that an experimental COVID19 vaccine, being developed by the University of Oxford, was safe and produced an immune response in early- stage clinical trials in healthy volunteers.
The Vaccine called AZD1222 ( ChAdOx1 nCoV-19 ) did not prompt any serious side effects and elicited antibody and T-cell immune responses, according to trial result published by the Lancet medical journal.
The vaccine is being developed by the Pharmaceutical company AstraZeneca and scientists at Britain’s University of Oxford.
More research would be required to confirm the efficacy of the vaccine and to know for how long any protection lasts.
According to reports, AstraZeneca has signed agreements with governments around the world to supply the vaccine should it prove effective and gain regulatory approval. The company has said it will not seek to profit from the vaccine during the pandemic.
I am no advertiser for the pharmaceutical company, but if they are keeping their word, then it would be a great gesture towards humanity.
Immune System
When germs, like bacteria or viruses invade the body, they attack and multiply. This invasion, called an infection is what causes an illness.
Blood contains RBC for carrying oxygen to tissues and organs and WBC for fighting infection.
The White Blood Cells( WBCs) consists of -
- [ ] Macrophages- swallow up and digest germs and dying cells. The macrophages leaves behind parts of invading germ cells called antigens. The body identifies these antigens as dangerous and stimulates antibodies to attack them.
- [ ] B- lymphocytes- are defensive white blood cells. They produce antibodies to attack the antigens left behind by macrophages.
- [ ] T-lymphocytes- Is another type of defensive WBC. They attack cells in the body that have already been infected.
The first time the body encounters a germ, it takes time for the body to get over the infection.
After the infection, the body remembers and keeps a few T- lymphocytes called Memory Cells. These gets activated when the body encounters the germ again.
When the similar antigens are detected, the B-lymphocytes produces antibodies to attack them.
How does Vaccine work ?
Vaccines help develop immunity by imitating an infection. This type of infection, rarely causes illness, but it causes the immune system to produce T- lymphocytes and antibodies.
Once the imitation infection goes away, the body is left with a supply of “memory” T- lymphocytes as well as B- lymphocytes that will remember how to fight the infection in future.
Types of Vaccines-
- [ ] Live attenuated - fights viruses and bacteria. Contains a version of the living virus or bacteria that has been weakened so that it does not cause disease in healthy individuals. Eg. MMR ( measles, mumps, rubella ) vaccine, varicella ( chickenpox) vaccine. People with weakened immune systems cannot get this live vaccine.
- [ ] Inactivated Vaccine- fight virus and bacteria. This vaccine is made by inactivating or killing the germ while making the vaccine. Eg. Inactivated polio vaccine. Often multiple doses are required to get the desired immunity and maintain it.
- [ ] Toxoid Vaccines - prevents diseases caused by bacteria that produce toxins ( poisons) in the body. Weakened toxins are called toxoids. When immune system receives a weakened toxin, it learns how to fight a toxin. Eg. DTP ( Diphtheria, Tetanus ) vaccine.
- [ ] Subunit Vaccine - includes only parts of virus or bacteria or subunits, instead of the entire germ. Since the whole germ is not present, side effects are less common. Eg. Pertussis ( whooping cough ) component of DTP vaccine.
- [ ] Conjugate Vaccine - fight different kind of bacteria. These bacteria have outer coating of sugar like substance called polysaccharides. This type of coating disguises the antigen, making it hard for young child’s immune system to recognise and respond to it. Conjugate vaccines are effective for these type of bacteria because they connect (conjugate) the polysaccharides to antigens. This linkage helps the immune system to react to the coating and develop an immune response. Eg. Hemophilus influenzae type B (Hib) vaccine.
Four reasons why Vaccines require more than one dose -
- [ ] For some vaccines ( inactivated vaccines) the first dose do not provide complete immunity.
- [ ] For some vaccines after some time immunity begins to wear off. So booster doses are required to bring immunity levels back up.
- [ ] For some vaccines ( live vaccines) studies have shown that more than one dose is required for best immune response. Eg. MMR vaccine
- [ ] In case of Flu vaccines, adults and children need to get a dose every year ( most important point as far as we are concerned, as we are in the middle of a flu pandemic ).
(Inputs from cdc.gov)
I started this article by saying I had a good nights sleep. Waking up and hearing news about two students contracting COVID19 after attending the KEAM Kerala engineering entrance examination has caused further alarm and dampened my spirits.
That an entrance examination was conducted at this juncture is outright foolish. There were even students who were under self quarantine who wrote exams!! Pictures of students huddled together have emerged from few schools in the capital Thiruvananthapuram.
I am no one to advise the government on any matter. They have great experts who advise them and rightly so.
As a concerned citizen this writer personally feels it would be prudent for the Government to take sound advise before going for such adventure, apparently just to add to their so called PR work led image management.
Until a safe and successful vaccine is out in the market, such antics and adventures should be avoided. It is useless to appeal to this Government.
Hope at least the Government advisors and experts takes notice.
Food for Thought.......
RC
It was with a kind of satisfaction that I had gotten to sleep yesterday night. The reason was of course that an experimental COVID19 vaccine, being developed by the University of Oxford, was safe and produced an immune response in early- stage clinical trials in healthy volunteers.
The Vaccine called AZD1222 ( ChAdOx1 nCoV-19 ) did not prompt any serious side effects and elicited antibody and T-cell immune responses, according to trial result published by the Lancet medical journal.
The vaccine is being developed by the Pharmaceutical company AstraZeneca and scientists at Britain’s University of Oxford.
More research would be required to confirm the efficacy of the vaccine and to know for how long any protection lasts.
According to reports, AstraZeneca has signed agreements with governments around the world to supply the vaccine should it prove effective and gain regulatory approval. The company has said it will not seek to profit from the vaccine during the pandemic.
I am no advertiser for the pharmaceutical company, but if they are keeping their word, then it would be a great gesture towards humanity.
Immune System
When germs, like bacteria or viruses invade the body, they attack and multiply. This invasion, called an infection is what causes an illness.
Blood contains RBC for carrying oxygen to tissues and organs and WBC for fighting infection.
The White Blood Cells( WBCs) consists of -
- [ ] Macrophages- swallow up and digest germs and dying cells. The macrophages leaves behind parts of invading germ cells called antigens. The body identifies these antigens as dangerous and stimulates antibodies to attack them.
- [ ] B- lymphocytes- are defensive white blood cells. They produce antibodies to attack the antigens left behind by macrophages.
- [ ] T-lymphocytes- Is another type of defensive WBC. They attack cells in the body that have already been infected.
The first time the body encounters a germ, it takes time for the body to get over the infection.
After the infection, the body remembers and keeps a few T- lymphocytes called Memory Cells. These gets activated when the body encounters the germ again.
When the similar antigens are detected, the B-lymphocytes produces antibodies to attack them.
How does Vaccine work ?
Vaccines help develop immunity by imitating an infection. This type of infection, rarely causes illness, but it causes the immune system to produce T- lymphocytes and antibodies.
Once the imitation infection goes away, the body is left with a supply of “memory” T- lymphocytes as well as B- lymphocytes that will remember how to fight the infection in future.
Types of Vaccines-
- [ ] Live attenuated - fights viruses and bacteria. Contains a version of the living virus or bacteria that has been weakened so that it does not cause disease in healthy individuals. Eg. MMR ( measles, mumps, rubella ) vaccine, varicella ( chickenpox) vaccine. People with weakened immune systems cannot get this live vaccine.
- [ ] Inactivated Vaccine- fight virus and bacteria. This vaccine is made by inactivating or killing the germ while making the vaccine. Eg. Inactivated polio vaccine. Often multiple doses are required to get the desired immunity and maintain it.
- [ ] Toxoid Vaccines - prevents diseases caused by bacteria that produce toxins ( poisons) in the body. Weakened toxins are called toxoids. When immune system receives a weakened toxin, it learns how to fight a toxin. Eg. DTP ( Diphtheria, Tetanus ) vaccine.
- [ ] Subunit Vaccine - includes only parts of virus or bacteria or subunits, instead of the entire germ. Since the whole germ is not present, side effects are less common. Eg. Pertussis ( whooping cough ) component of DTP vaccine.
- [ ] Conjugate Vaccine - fight different kind of bacteria. These bacteria have outer coating of sugar like substance called polysaccharides. This type of coating disguises the antigen, making it hard for young child’s immune system to recognise and respond to it. Conjugate vaccines are effective for these type of bacteria because they connect (conjugate) the polysaccharides to antigens. This linkage helps the immune system to react to the coating and develop an immune response. Eg. Hemophilus influenzae type B (Hib) vaccine.
Four reasons why Vaccines require more than one dose -
- [ ] For some vaccines ( inactivated vaccines) the first dose do not provide complete immunity.
- [ ] For some vaccines after some time immunity begins to wear off. So booster doses are required to bring immunity levels back up.
- [ ] For some vaccines ( live vaccines) studies have shown that more than one dose is required for best immune response. Eg. MMR vaccine
- [ ] In case of Flu vaccines, adults and children need to get a dose every year ( most important point as far as we are concerned, as we are in the middle of a flu pandemic ).
(Inputs from cdc.gov)
I started this article by saying I had a good nights sleep. Waking up and hearing news about two students contracting COVID19 after attending the KEAM Kerala engineering entrance examination has caused further alarm and dampened my spirits.
That an entrance examination was conducted at this juncture is outright foolish. There were even students who were under self quarantine who wrote exams!! Pictures of students huddled together have emerged from few schools in the capital Thiruvananthapuram.
I am no one to advise the government on any matter. They have great experts who advise them and rightly so.
As a concerned citizen this writer personally feels it would be prudent for the Government to take sound advise before going for such adventure, apparently just to add to their so called PR work led image management.
Until a safe and successful vaccine is out in the market, such antics and adventures should be avoided. It is useless to appeal to this Government.
Hope at least the Government advisors and experts takes notice.
Food for Thought.......
RC
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