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Derek Lowe over at Science has a roundup of the status of current (article published 29 June 2020) Coronavirus vaccine trials/research.
This roundup of current vaccine research/trials includes information about many vaccine trials, broken down by vaccine types. These types include (quotes are all from TFA:
- Viral Vectors
This class uses some other infectious virus, but with its original genetic material removed. In its place goes genetic instructions to make coronavirus proteins, and when your infected cells do that, it will set off an immune response.
Number of trials (per TFA): 9
- Genetic Vaccines
These take DNA or RNA coding for coronavirus proteins and inject that directly into the bloodstream. "Directly" isn't quite the right word, though – for these things to work, they have to be formulated and modified to survive destruction in the blood, to be taken up through cell membranes, and to be used for protein production once they're inside.
Number of trials (per TFA): 8
- Recombinant protein vaccines
Here we get to a technique that really is used for human vaccines. The previous two categories force your own cells to make viral antigen proteins, but here you're making them industrially and just injecting them directly. The advantage can be that such protein production can be accomplished in many different ways and is already done on a large scale. That said, every new protein is a new project, with its own idiosyncrasies.
Number of trials (per TFA): 6
- Attenuated Virus Vaccines
This is another well-precedented vaccination technique. It involves producing a weakened form of the actual infectious virus, one that is not capable of causing damage but can still set off the immune system. There are several ways to do this, and it's a bit of an art form involving taking the virus through a huge number of replications in living cells as you select for variants that are less and less harmful.
Number of trials (per TFA): (None listed)
- Inactivated Virus Vaccines
This is also one that's also been used in medical practice for many years, and it's another inactivation step beyond the attenuated viruses. Heat or chemical agents are used to damage the virus to the point that it can no longer infect cells at all, but the plan is for there to be enough of the viral material left unaltered to still raise an immune response.
Number of trials (per TFA): 4
(Score: 1, Insightful) by Anonymous Coward on Saturday July 04 2020, @01:02PM (1 child)
Who modded this informative? It's actually a misleading post, particularly because it conflates issues with flu vaccines and the likelihood of only having short term immunity to coronaviruses.
The effectiveness of flu vaccines depends on preparing a vaccine for the correct strains of the virus. Influenza mutates rapidly, but there can be long term immunity to some strains. For example, older people were less susceptible to the Spanish flu. It's believed this is partly due to having been exposed to a similar strain of the virus, particularly the Russian flu in 1889.
The coronaviruses that infect humans don't mutate rapidly in significant ways. There are small amounts of genetic drift, which has been observed in SARS-CoV-2. But more significant mutations are rare. I agree that long term immunity is very unlikely. But there is likely short term immunity for a few months or perhaps a couple of years. This virus hasn't been circulating long enough to really know how long immunity lasts, but it's probably similar to other coronaviruses like SARS and MERS. Because the mutation rate in these coronaviruses is low, that removes one of the main challenges associated with flu vaccines. Even a vaccine that provides partial immunity, such as making infections much less severe, would be helpful. Later vaccines may provide more complete immunity. Even if vaccines only provide immunity for a couple of years, people can periodically be vaccinated to maintain immunity.
Issues with flu vaccines are caused by the high mutation rate associated with the virus. That's not an issue with the coronaviruses that infect humans.
(Score: 0) by Anonymous Coward on Sunday July 05 2020, @07:16AM
No shit. "If it's only as effective as the flu vaccine," GP says. Well, if it were that effective then this epidemic would be over in a matter of weeks. Coronaviruses aren't Influenza viruses, and differ in multiple important ways. And that is before you get into this Coronavirus in particular and its properties compared to the entire group of Coronaviruses.