请再多科普一些内容,优缺点,有效性,有效期,副作用,价格,适用面...
不是很确定第3项腺病体疫苗的英文是什么?不知是不是俄国和陈薇的这类。
1. Inactivated virus
In this case, the virus is grown in large quantities in cells, and then killed, often with a chemical, which is usually formaldehyde, but heat or radiation can also be used. Two kinds of flu vaccines are made this way, grown in either chicken eggs or mammalian cells.
Pros
- Unlike live virus vaccines, it can even be given to people with weakened immune systems.
Cons
- It doesn't lead to as strong an immune response as a live virus. Several doses, including boosters at regular intervals, are usually necessary.
- It requires the virus to be grown in large quantities and that can take time and may not be as easy to scale up as other kinds of vaccines.
2. RNA
With RNA vaccines, what's injected into the body is simply the genetic instructions to make a viral protein such as the spike protein. Cells in your body then use the instructions to make the protein inside the body for your immune cells to see and respond to.
Pros
- No virus is needed to make the vaccine, cutting production time compared to conventional vaccines.
Cons
- Don't always produce a strong immune response compared to whole viruses, and may require adjuvants.
3. Non-replicating viral vector
Viral vectors are "carrier" viruses that don't cause the disease you're vaccinating against, such as COVID-19, but can be engineered to carry a piece of viruses such as SARS-CoV-2. Non-replicating viral vectors are viruses that have been genetically engineered so they can't replicate and cause disease. Then they're further modified to produce the protein for the disease you want, such as the coronavirus spike protein, and injected into the body to provoke an immune response.
The viruses used by COVID-19 vaccine candidates include adenoviruses, MVA (modified vaccinia ankara, a weakened pox virus), parainfluenza and rabies.
Pros
- Generates more powerful immune response than subunit proteins.
- Some don't have to be stored at very low temperatures (according to China-based company CanSino), so they're viable for use in resource-limited tropical areas.
Cons
- People who have already been exposed to the viral vector, such as adenovirus, may be resistant.
- Harder to scale up than protein or DNA because a virus still needs to be grown.
- Because each virus can only infect one cell, large quantities of the virus need to be grown and injected, adding to production time.