Showing posts with label Covid-19. Show all posts
Showing posts with label Covid-19. Show all posts

What happens if Corona virus vaccine is never developed


As of 14th May 2020 there are at least 95 vaccines under various stages of development to prevent Covid-19. Recently Pfizer begins human trials of possible corona virus vaccine. Oxford covid-19 vaccine's human trial results will arrive by June, Researcher confirms.



Vaccine - The Panacea

Historically, vaccines have been one of the greatest public health tools to prevent disease. But even as new technology, advancements in genomics and improved global coordination have allowed researchers to move at unprecedented speed, vaccine development remains an expensive and risky process.


Long Process

  • It takes months and even years just to start human trials of vaccines.
  • Vaccines makers around the world are racing to speed up their timelines for development, a process that typically takes years.
  • Companies/Universities are making extraordinary efforts to stagger trials and, in some cases, skip essential steps, such as animal testing.


Worst case scenario

  • There is another worst case possibility - that no vaccine is ever developed.
  • After the SARS outbreak in 2003, it takes researchers about 20 months from the release of the viral genome to get a vaccine ready for human trials.
  • 2020- no vaccine ready for deployment. Recently WHO envoy warns corona virus vaccine may never be developed.


Plan B

Pre-exposure prophylaxis options.
  • Remdesivir
  • HCQ
But, we required randomized controls trials for these two options.

Life without vaccine

  • Instead of wiping out Covid-19, societies may instead learn to live with it.
  • Treatments may be developed. But, outbreaks of the disease still occur each year(peaking in winters).
  • Cities would slowly re-open. But, shut again anytime.
  • Abrupt instruction to self-isolate could come at any time.

Last option - Herd immunity

When most of a population is immune to an infectious disease, this provides indirect protection or herd immunity(also called herd protection) to those who are not immune to the disease. For example, if 80% of a population is immune to a virus, four out of every five people who encounter someone with the disease won’t get sick(and won’t spread the disease any further). In this way, the spread of infectious diseases is kept under control. Depending how contagious an infection is, usually 70% to 90% of a population needs immunity to achieve herd immunity


There are many more diseases without vaccines

  • HIV (AIDS) - 4 decades and 32 million deaths later, the world is still waiting for an HIV vaccine. HIV mutates during a single infection. It continues to mutate inside the body. So, it's like you're infected with a thousand different HIV strands.
  • Malaria - 230 million cases and 0.4 million deaths annually.
  • Dengue - Vaccine developed recently in 2015 but failed in field.
  • Influenza is able to change itself from one year to the next. So, it is extremely hard to find vaccine for it.
Vaccines are the tugboats of preventive health
-William Foege

Plasma Therapy for Corona virus


Plasma therapy for Covid-19

Corona virus disease is an infectious disease. Nowadays Plasma therapy is widely used for fighting against corona virus. Let's see what is Plasma therapy? how it is useful? and is this the cure for corona virus pandemic?

What is Plasma?

Plasma is the little yellowish liquid component of the blood. It carries cells and proteins throughout the body. It makes up about 55% of the body's total blood volume. Blood serum is blood plasma without clotting factors. Plasmapheresis is a medical therapy that involves blood plasma extraction, treatment, and reintegration.

Convalescent plasma therapy

Convalescent is the process of recovering from an illness or medical treatment.
  • When people get sick with a virus or bacteria, they recover from the illness because their body produces antibodies specifically to fight that 'ANTIGEN'.
  • Vaccines also spur the body into producing these protective antibodies.
  • But there is no Covid-19 vaccine yet, so plasma from recovered patients remains doctors' best source of antibodies for now.

Plasma from patients who have recovered from Covid-19 will contain antibodies that their immune systems have produced in fighting the virus. That plasma can be transfused to patients whose own immune systems are struggling to develop their own antibodies. The plasma transfusion is therefore intended to provide the poorly patient to help their body fight the covid-19 virus.


What is Antibody?

An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses. Antibodies are secreted by B cells of the adaptive immune system. The antibody recognizes a unique molecule of the pathogen(antigen), attaches to it and activates other parts of immune system to attack the 'foreign' antigen.


What is the process?

  • To get the plasma, people who have fully recovered from the infection must first donate blood. Donors must be free of symptoms for at lease 14 days.
  • The plasma is then separated from the blood in a process called plasmapheresis and screened for toxins or infections, like hepatitis or HIV. Next the plasma is tested to make sure it has enough antibodies to effectively treat or prevent Covid-19.
  • After that, it can be infused into the recipient through a procedure that's similar to a blood transfusion and is known to be safe.


This technique is not a new. Horse serum is used for creating vaccines for diphtheria, tetanus and scarlet fever. This technique is not useful in all the kind of diseases. As per the report china conducted this test in February and succeed.


Various trials and studies

  • In Shenzhen, China doctors used Convalescent plasma in some patients with encouraging results.
  • The study found that the therapy was safe and cleared the virus in seven out of ten patients.
  • Plasma from recovered patients has also been used in outbreaks of Ebola, as well as other corona viruses, like SARS(severe acute respiratory syndrome) and MERS(Middle East respiratory syndrome), Spanish flu(100 years ago), H1N1 swine flu(10 years ago).


Is this the cure for Covid-19?

No, This is not the cure for Covid-19. Convalescent plasma is a stopgap measure until a better treatment or vaccine is available. The therapy will be useful on people who have been hospitalized with Covid-19 but are not yet in critical condition. If the treatment can prevent those people from ending up in the intensive care unit, It will free up valuable resources like beds and ventilators fro patients with more severe illness.


Challenges

One of the challenges of plasma therapy will be administering it in the right window of time to provide the maximum boost to a person's immune system. The sooner it can be given(ideally, within a few days after exposure or the onset of symptoms), the better a person will likely fare. After that, patients might be too far along in the course of their disease to benefit. The timing could be tricky, because some people aren't admitted to the hospital until many days after their illness has begun.


Keep calm and carry on...