"India shows why we will all need COVID vaccine booster shots
COVID mutations could spin out of control if situations like that in India continue to occur. Dr Khan explains how boosters will work...
...The mass production of the COVID-19 vaccines has been nothing short of a feat of medical science, and the rollout across many countries has been incredible. But there is a fly in the ointment – two, to be precise: How long does the protection provided by a vaccine last? And, will the vaccines be effective against emerging variants?
The tragic situation unfolding in India is a case in point when it comes to fighting new variants of the coronavirus. India has a population of 1.4 billion and had an excellent start to its vaccination programme. It is also home to one of the biggest manufacturers of vaccines in the world: the Serum Institute of India (SII), which was making and exporting millions of vaccines to other countries as cases were coming down in India.
But due to recent public gatherings, and the early easing of lockdown measures, India has found itself at the epicentre of the pandemic, setting global records for daily cases and deaths. The world has watched in horror as scenes of people struggling to breathe outside hospitals have streamed across news networks.
The SII and the Indian government have now reduced the volume of vaccine being exported from India, but this has come too late as they are also struggling to obtain the raw materials needed for vaccine manufacture from the United States, which is focused on getting its own population vaccinated.
This highlights the problem of Western countries prioritising their own vaccinations while other countries miss out. It also shines a light on holes in the World Health Organization’s plans to get vaccines to poorer countries through its COVAX scheme. As the pandemic unfolds, it is becoming clearer that there are likely to be huge outbreaks in some countries, and a global firefighting approach will most likely be needed. India is one of the world’s fastest growing economies, but the pandemic has brought it to its knees, forced to ask for foreign aid.
The longer the virus is able to run riot in India, the more people it will infect and the more likely it is that further mutations will emerge.
Scientists believe the latest Indian “double mutant” variant exhibit traits that could make it more infectious and less susceptible to vaccine-induced immunity, and we may well see the virus mutate further and in a direction that will make the current batch of vaccines even less effective.
As new variants emerge, therefore, we are likely to need booster shots to maintain our levels of protection or to fight new variants.
How long does protection from a COVID vaccine last?
Another issue is that we do not know for sure how long protection lasts after having a COVID-19 vaccine. Most experts agree that protection is likely to last at least six months but only time will tell and further research is needed.
According to a study of 927 people, conducted by Pfizer and published on April 1, 2021, the vaccine offered 91.3 percent protection against COVID-19, measured from seven days through to six months after the second dose.
The company is also conducting a study into the effectiveness of a third dose of the vaccine – essentially a booster, given six to 12 months after the second dose. The study is part of Pfizer’s clinical development strategy to determine the effectiveness of a third dose of the same vaccine against evolving variants.
A study looking at the length of time the Moderna vaccine gives protection also showed those people who were given two doses of the vaccine had good antibody levels at six months after the second dose.
There is less data available for the Oxford-AstraZeneca vaccine. However, when looking at the effectiveness of the vaccine after giving the two doses at different intervals, studies have shown that the vaccine efficacy reached 82.4 percent after a second dose for those who had a dosing interval of 12 weeks or more, meaning if the two doses are given at least three months apart they offer more than 82 percent protection. It is therefore reasonable to think the protection will last at least a further three months after the second dose, although more data is needed.
It is entirely possible that vaccine-induced protection will last longer than the six months being proposed by these findings, but many experts believe that the antibodies created by vaccines will wane over time and booster shots will be required.
How will boosters work?
Booster shots work like a wake-up call for your immune system. Vaccines stimulate the body to create antibodies that are capable of recognising the coronavirus and, should you encounter it, killing it and any cells that have been infected by it, usually before you develop any symptoms.
Once this is complete, memory T and B immune cells patrol the body in case another encounter occurs. Over time, the numbers of these memory cells start to dwindle and the immune system may “forget” how to recognise the pathogen or germ causing the illness effectively in the future.
Booster shots serve to “remind” the immune system how to recognise the specific pathogen causing the disease. It means your body is more likely to respond quickly and more effectively after a booster shot.
According to Albert Bourla, the chief executive at Pfizer, the answer to whether we will need booster shots is “yes”. Speaking with American healthcare company CVS Health on April 16, Bourla said: “There will be likely a need for a third dose somewhere between six and 12 months [following the first two doses] and then from there, there will be an annual revaccination.”
Nadhim Zahawi, the UK’s vaccine minister, has said people who are clinically extremely vulnerable could begin to receive booster shots against new coronavirus variants as early as September. And David Kessler, chief science officer to the White House coronavirus task force, spoke to a congressional committee in the US about the need for booster shots, saying: “We understand that at a certain point in time we need to boost, whether that’s nine months, 12 months, and we are preparing for that coming.”
Booster shots are not a new phenomenon; we use them for other vaccines. We give booster shots of the measles, mumps, rubella (MMR) vaccine to children to ensure longer lasting and effective immunity and we give annual flu vaccines to clinically vulnerable people to protect against new strains of the flu virus.
Can boosters protect us from new variants?
New variants of the coronavirus are emerging all over the world. Only a handful are “variants of concern” – those that may harbour mutations enabling them to evade our immune responses triggered by vaccines. Booster shots may also serve as a way to stimulate the body to recognise new variants of the coronavirus as well.
Variants of concern include the South African, Brazil and Indian variants which have emerged in recent months (the vaccines appear to be effective against the UK variant). These variants include mutations of the spike protein (the part of the virus that binds to human cells) which might make them harder to recognise by immune cells generated by vaccines.
If these variants become dominant variants or more widespread then booster shots which can protect us against them are likely to be needed. If vaccines do need to be tweaked to be more effective against new variants, manufacturers have said that these will be easy to do and can be done in less than three months.
As time goes on, it is looking more and more likely that booster shots against COVID-19 are going to be needed. Many people argue that there is going to be a never-ending cycle of vaccines and boosters, but we already tolerate this with flu each year and we should start to look at vaccines against the coronavirus as no different to that.
Progress report: A possible vaccine for malaria
Another serious disease that kills some 400,000 people every year is malaria. But, at last, there may be a solution in sight. On April 23, researchers from the University of Oxford and its partners announced some promising results from tests of its vaccine which they claim is 77 percent effective in preventing malaria – higher than the World Health Organization (WHO) target efficacy of 75 percent.
www.aljazeera.com
COVID mutations could spin out of control if situations like that in India continue to occur. Dr Khan explains how boosters will work...
...The mass production of the COVID-19 vaccines has been nothing short of a feat of medical science, and the rollout across many countries has been incredible. But there is a fly in the ointment – two, to be precise: How long does the protection provided by a vaccine last? And, will the vaccines be effective against emerging variants?
The tragic situation unfolding in India is a case in point when it comes to fighting new variants of the coronavirus. India has a population of 1.4 billion and had an excellent start to its vaccination programme. It is also home to one of the biggest manufacturers of vaccines in the world: the Serum Institute of India (SII), which was making and exporting millions of vaccines to other countries as cases were coming down in India.
But due to recent public gatherings, and the early easing of lockdown measures, India has found itself at the epicentre of the pandemic, setting global records for daily cases and deaths. The world has watched in horror as scenes of people struggling to breathe outside hospitals have streamed across news networks.
The SII and the Indian government have now reduced the volume of vaccine being exported from India, but this has come too late as they are also struggling to obtain the raw materials needed for vaccine manufacture from the United States, which is focused on getting its own population vaccinated.
This highlights the problem of Western countries prioritising their own vaccinations while other countries miss out. It also shines a light on holes in the World Health Organization’s plans to get vaccines to poorer countries through its COVAX scheme. As the pandemic unfolds, it is becoming clearer that there are likely to be huge outbreaks in some countries, and a global firefighting approach will most likely be needed. India is one of the world’s fastest growing economies, but the pandemic has brought it to its knees, forced to ask for foreign aid.
The longer the virus is able to run riot in India, the more people it will infect and the more likely it is that further mutations will emerge.
Scientists believe the latest Indian “double mutant” variant exhibit traits that could make it more infectious and less susceptible to vaccine-induced immunity, and we may well see the virus mutate further and in a direction that will make the current batch of vaccines even less effective.
As new variants emerge, therefore, we are likely to need booster shots to maintain our levels of protection or to fight new variants.
How long does protection from a COVID vaccine last?
Another issue is that we do not know for sure how long protection lasts after having a COVID-19 vaccine. Most experts agree that protection is likely to last at least six months but only time will tell and further research is needed.
According to a study of 927 people, conducted by Pfizer and published on April 1, 2021, the vaccine offered 91.3 percent protection against COVID-19, measured from seven days through to six months after the second dose.
The company is also conducting a study into the effectiveness of a third dose of the vaccine – essentially a booster, given six to 12 months after the second dose. The study is part of Pfizer’s clinical development strategy to determine the effectiveness of a third dose of the same vaccine against evolving variants.
A study looking at the length of time the Moderna vaccine gives protection also showed those people who were given two doses of the vaccine had good antibody levels at six months after the second dose.
There is less data available for the Oxford-AstraZeneca vaccine. However, when looking at the effectiveness of the vaccine after giving the two doses at different intervals, studies have shown that the vaccine efficacy reached 82.4 percent after a second dose for those who had a dosing interval of 12 weeks or more, meaning if the two doses are given at least three months apart they offer more than 82 percent protection. It is therefore reasonable to think the protection will last at least a further three months after the second dose, although more data is needed.
It is entirely possible that vaccine-induced protection will last longer than the six months being proposed by these findings, but many experts believe that the antibodies created by vaccines will wane over time and booster shots will be required.
How will boosters work?
Booster shots work like a wake-up call for your immune system. Vaccines stimulate the body to create antibodies that are capable of recognising the coronavirus and, should you encounter it, killing it and any cells that have been infected by it, usually before you develop any symptoms.
Once this is complete, memory T and B immune cells patrol the body in case another encounter occurs. Over time, the numbers of these memory cells start to dwindle and the immune system may “forget” how to recognise the pathogen or germ causing the illness effectively in the future.
Booster shots serve to “remind” the immune system how to recognise the specific pathogen causing the disease. It means your body is more likely to respond quickly and more effectively after a booster shot.
According to Albert Bourla, the chief executive at Pfizer, the answer to whether we will need booster shots is “yes”. Speaking with American healthcare company CVS Health on April 16, Bourla said: “There will be likely a need for a third dose somewhere between six and 12 months [following the first two doses] and then from there, there will be an annual revaccination.”
Nadhim Zahawi, the UK’s vaccine minister, has said people who are clinically extremely vulnerable could begin to receive booster shots against new coronavirus variants as early as September. And David Kessler, chief science officer to the White House coronavirus task force, spoke to a congressional committee in the US about the need for booster shots, saying: “We understand that at a certain point in time we need to boost, whether that’s nine months, 12 months, and we are preparing for that coming.”
Booster shots are not a new phenomenon; we use them for other vaccines. We give booster shots of the measles, mumps, rubella (MMR) vaccine to children to ensure longer lasting and effective immunity and we give annual flu vaccines to clinically vulnerable people to protect against new strains of the flu virus.
Can boosters protect us from new variants?
New variants of the coronavirus are emerging all over the world. Only a handful are “variants of concern” – those that may harbour mutations enabling them to evade our immune responses triggered by vaccines. Booster shots may also serve as a way to stimulate the body to recognise new variants of the coronavirus as well.
Variants of concern include the South African, Brazil and Indian variants which have emerged in recent months (the vaccines appear to be effective against the UK variant). These variants include mutations of the spike protein (the part of the virus that binds to human cells) which might make them harder to recognise by immune cells generated by vaccines.
If these variants become dominant variants or more widespread then booster shots which can protect us against them are likely to be needed. If vaccines do need to be tweaked to be more effective against new variants, manufacturers have said that these will be easy to do and can be done in less than three months.
As time goes on, it is looking more and more likely that booster shots against COVID-19 are going to be needed. Many people argue that there is going to be a never-ending cycle of vaccines and boosters, but we already tolerate this with flu each year and we should start to look at vaccines against the coronavirus as no different to that.
Progress report: A possible vaccine for malaria
Another serious disease that kills some 400,000 people every year is malaria. But, at last, there may be a solution in sight. On April 23, researchers from the University of Oxford and its partners announced some promising results from tests of its vaccine which they claim is 77 percent effective in preventing malaria – higher than the World Health Organization (WHO) target efficacy of 75 percent.
India shows why we will all need COVID vaccine booster shots
COVID mutations could spin out of control if situations like that in India continue to occur.
