Nine vaccines have been effective in protecting people from developing symptoms of Covid-19, the infection that can be caused by infection with the SARS-CoV-2 virus. It is not yet known, however, how well the inoculations prevent people from transmitting asymptomatic diseases or the virus to others. Starting signs suggest that they do at least some of both.
Live updates: Coronavirus pandemic
1. Why is this important?
Although the vaccine gives people a lot of insurance against becoming ill with Covid, which is sometimes fatal, there is no guarantee so far that they will not get a quiet grip with SARS-CoV-2 and give it away, potentially ill people who are not immune. Those who are infected but do not develop symptoms are responsible for 24% of transmission, one study has estimated.
The more SARS-CoV-2 circulates, the more the virus has a chance to circulate in ways that increase its ability to spread, infect and kill humans, and bypass the immunity provided by the virus. existing vaccines or past infections. Already, variants of the virus have emerged that appear to be more dangerous. Also, with the use of vaccines for so-called herd protection, when an entire community is protected even though not everyone has been vaccinated, vaccines that prevent transmission are required.
2. Do vaccines not stop infection and therefore give them?
Some do and some don’t. The gold standard in vaccines is to prevent infection as well as disease – providing sterilizing immunity. But it is not always accomplished. The measles vaccine, for example, is given; the one is not for hepatitis B.
Pandemic coronavirus: Full coverage
3. Do Covid vaccines need to prevent infection to stop the spread?
Not necessary. To the extent that a vaccine prevents infection, it also prevents the spread. But he can do the last one without doing the first one. Because SARS-CoV-2 is transmitted through the respiratory tract from the throat and nose of an infected person, a vaccine that reduces the duration of the infection, the level of virus in the respiratory tract (the viral load), or its frequency in which an infected person may cough has reduced the likelihood of transmission to others.
4. Why don’t we know if Covid vaccines prevent infection and transmission?
The trials testing the vaccines were not set up to answer these questions initially. Instead, they were designed to test the more pressing issue of whether vaccines would stop people from becoming ill and overcoming medical systems. To investigate that question, researchers typically administered the experimental vaccine to one group of volunteers and another placebo to another group of similar size. After the total number of volunteers with Covid symptoms confirmed in the test reached a predetermined level, researchers compared the number in each group to see if those who received the vaccine were significantly more better than those who received the placebo. For the inoculations that have worked, the vaccine groups have been anywhere from 50% to 95% fewer cases of illness, figures known as vaccine efficacy levels.
5. Why not check out volunteers for asymptomatic diseases as well?
That’s a more complicated task because the only way to experience asymptomatic diseases is to regularly test volunteers, who can count into tens of thousands in an effectiveness test. However, there are about two dozen studies in which the vaccines tested to prevent infection do just that.
6. What did they find?
The results so far are preliminary. The most widely released data relates to the vaccine produced by AstraZeneca Plc. In a UK study, volunteers are screened for SARS-CoV-2 infections using weekly self-administered nose and throat swabs. According to results from December 7, after a single dose, the vaccinated group had 67% fewer advanced swabs than the placebo group, suggesting that the vaccine cuts down on infections as well as disease. Earlier, Moderna Inc. an account of similar results from people who had received a single dose of the vaccine since November.
7. What other evidence do we have?
Data from Israel, which has imported a higher percentage of its population than any other country, suggests that the vaccine used there, from Pfizer Inc. and BioNTech SE, to reduce the transmission even if it does not protect against disease. After more than 75% of people aged 60 and over received a single dose of vaccine and only 25% of those between the ages of 40 and 60, researchers from Israel’s largest coronavirus testing laboratory looked at the their data. For those who tested positive for SARS-CoV-2, there was a significant difference between the two age groups in the average number of viruses detected in test swabs. The researchers estimated that vaccination reduces the viral load by 1.6 to 20 times in infected individuals despite the burn. Another study in Israel found that after people suffered from vaccination, the vaccine reduced their viral load by four times. A study of the Moderna Covid vaccine in monkeys also suggested that it could, if not completely stop, reduce the spread of the virus.
8. When will we know more?
As the vaccine becomes more widely available, researchers should be able to identify the effect of infection and transmission patterns, although it may be difficult to differentiate the effect of inoculations from the effect of inoculations. measures such as locks and masonry orders. Completion of the test vaccine tests for asymptomatic diseases will provide additional information. Two trials are expected to be completed in April. However, one vaccine from Sinovac Biotech Ltd. in China, which has a reported efficacy rate as low as 50% against symptomatic disease. The other trials fire at the bullet of the Russian Gamaleya Research Institute, which had an efficacy against symptoms of 92% in clinical trials, but it is a small study. September should end major trials of highly effective vaccines. Results are not expected for the pictures that have been as effective in preventing disease (95%), from Moderna and Pfizer-BioNTech, to October 2022 and January 2023, respectively.
Live updates: Coronavirus pandemic
1. Why is this important?
Although the vaccine gives people a lot of insurance against becoming ill with Covid, which is sometimes fatal, there is no guarantee so far that they will not get a quiet grip with SARS-CoV-2 and give it away, potentially ill people who are not immune. Those who are infected but do not develop symptoms are responsible for 24% of transmission, one study has estimated.
The more SARS-CoV-2 circulates, the more the virus has a chance to circulate in ways that increase its ability to spread, infect and kill humans, and bypass the immunity provided by the virus. existing vaccines or past infections. Already, variants of the virus have emerged that appear to be more dangerous. Also, with the use of vaccines for so-called herd protection, when an entire community is protected even though not everyone has been vaccinated, vaccines that prevent transmission are required.
2. Do vaccines not stop infection and therefore give them?
Some do and some don’t. The gold standard in vaccines is to prevent infection as well as disease – providing sterilizing immunity. But it is not always accomplished. The measles vaccine, for example, is given; the one is not for hepatitis B.
Pandemic coronavirus: Full coverage
3. Do Covid vaccines need to prevent infection to stop the spread?
Not necessary. To the extent that a vaccine prevents infection, it also prevents the spread. But he can do the last one without doing the first one. Because SARS-CoV-2 is transmitted through the respiratory tract from the throat and nose of an infected person, a vaccine that reduces the duration of the infection, the level of virus in the respiratory tract (the viral load), or its frequency in which an infected person may cough has reduced the likelihood of transmission to others.
4. Why don’t we know if Covid vaccines prevent infection and transmission?
The trials testing the vaccines were not set up to answer these questions initially. Instead, they were designed to test the more pressing issue of whether vaccines would stop people from becoming ill and overcoming medical systems. To investigate that question, researchers typically administered the experimental vaccine to one group of volunteers and another placebo to another group of similar size. After the total number of volunteers with Covid symptoms confirmed in the test reached a predetermined level, researchers compared the number in each group to see if those who received the vaccine were significantly more better than those who received the placebo. For the inoculations that have worked, the vaccine groups have been anywhere from 50% to 95% fewer cases of illness, figures known as vaccine efficacy levels.
5. Why not check out volunteers for asymptomatic diseases as well?
That’s a more complicated task because the only way to experience asymptomatic diseases is to regularly test volunteers, who can count into tens of thousands in an effectiveness test. However, there are about two dozen studies in which the vaccines tested to prevent infection do just that.
6. What did they find?
The results so far are preliminary. The most widely released data relates to the vaccine produced by AstraZeneca Plc. In a UK study, volunteers are screened for SARS-CoV-2 infections using weekly self-administered nose and throat swabs. According to results from December 7, after a single dose, the vaccinated group had 67% fewer advanced swabs than the placebo group, suggesting that the vaccine cuts down on infections as well as disease. Earlier, Moderna Inc. an account of similar results from people who had received a single dose of the vaccine since November.
7. What other evidence do we have?
Data from Israel, which has imported a higher percentage of its population than any other country, suggests that the vaccine used there, from Pfizer Inc. and BioNTech SE, to reduce the transmission even if it does not protect against disease. After more than 75% of people aged 60 and over received a single dose of vaccine and only 25% of those between the ages of 40 and 60, researchers from Israel’s largest coronavirus testing laboratory looked at the their data. For those who tested positive for SARS-CoV-2, there was a significant difference between the two age groups in the average number of viruses detected in test swabs. The researchers estimated that vaccination reduces the viral load by 1.6 to 20 times in infected individuals despite the burn. Another study in Israel found that after people suffered from vaccination, the vaccine reduced their viral load by four times. A study of the Moderna Covid vaccine in monkeys also suggested that it could, if not completely stop, reduce the spread of the virus.
8. When will we know more?
As the vaccine becomes more widely available, researchers should be able to identify the effect of infection and transmission patterns, although it may be difficult to differentiate the effect of inoculations from the effect of inoculations. measures such as locks and masonry orders. Completion of the test vaccine tests for asymptomatic diseases will provide additional information. Two trials are expected to be completed in April. However, one vaccine from Sinovac Biotech Ltd. in China, which has a reported efficacy rate as low as 50% against symptomatic disease. The other trials fire at the bullet of the Russian Gamaleya Research Institute, which had an efficacy against symptoms of 92% in clinical trials, but it is a small study. September should end major trials of highly effective vaccines. Results are not expected for the pictures that have been as effective in preventing disease (95%), from Moderna and Pfizer-BioNTech, to October 2022 and January 2023, respectively.