Viruses in Vaccines that can mutate and spread

  • Thread starter new6ton
  • Start date
  • #1
new6ton
Gold Member
223
6

Main Question or Discussion Point

Besides Polio. What other viruses in vaccine can mutate and spread?

The Polio type 2 wild viruses were supposed to be eradicated already.

http://polioeradication.org/news-post/global-eradication-of-wild-poliovirus-type-2-declared/
But recently. It's resurging. Is there possibility that mutated viruses from vaccine can become airborned?

What kind of viruses can become airborned? Why doesn't it happen to the HIV virus?

"Vaccine-derived polio happens when live strains of poliovirus that are used in the oral poliovirus vaccine mutate, spread and, in rare cases, trigger an outbreak. Most of the time the virus dies off but it can sometimes spread in an area where there is low vaccination coverage."
 

Answers and Replies

  • #2
russ_watters
Mentor
19,319
5,354
Besides Polio. What other viruses in vaccine can mutate and spread?

The Polio type 2 wild viruses were supposed to be eradicated already.

http://polioeradication.org/news-post/global-eradication-of-wild-poliovirus-type-2-declared/
But recently. It's resurging. Is there possibility that mutated viruses from vaccine can become airborned?

What kind of viruses can become airborned? Why doesn't it happen to the HIV virus?

"Vaccine-derived polio happens when live strains of poliovirus that are used in the oral poliovirus vaccine mutate, spread and, in rare cases, trigger an outbreak. Most of the time the virus dies off but it can sometimes spread in an area where there is low vaccination coverage."
The quoted text is not in the link. What is the source?
 
  • #3
new6ton
Gold Member
223
6
Last edited:
  • #4
Ygggdrasil
Science Advisor
Insights Author
Gold Member
2019 Award
2,953
2,184
There are four main types of vaccines in common use today: 1) live, attenuated vaccines (LAVs), 2) inactivated vaccines, 3) subunit vaccines, and 4) toxin vaccines. Only LAVs carry the rare risk of infecting the individual who receives the vaccine. Inactivated vaccines contain dead virus, subunit vaccines carry only small pieces of the virus, and toxin vaccines carry portions of molecules created by pathogens (such as the bacterial toxins that cause tetanus).

LAVs are created by manufacturing versions of the virus that contain mutations that should prevent the virus from replicating inside of the host. In rare instances, these mutations can revert to their original forms to produce a virus capable of replicating and causing disease. This occurs very rarely (e.g. the World Health Organization says that the oral polio vaccine causes polio in only 0.0002 – 0.0004% of cases; for every million people that are vaccinated, only 2-4 individuals will become infected).

LAVs are not more prone to other types of mutations than the normal virus, and would not have an increased risk acquiring mutations that confer new traits such as becomming airborne. In the case of a LAV becoming infectious, the mutations are restoring an ability to the virus that we knew the virus was already capable of performing. Mutations that confer new abilities to a virus (e.g. causing a non-airborne virus to become airborne) are observed very rarely. LAVs would be much less likely to contribute to the evolution of a new virus that viruses in the wild because: 1) the virus is incompetent for replication and already requires several mutations to become infectious again, so additional mutations on top of those would be even more rare, and 2) individuals infected with LAVs are presumably living under conditions where others around them are being vaccinated, so the virus would have difficulty finding unvaccinated hosts.

For more information about the different types of vaccines, see:
https://www.vaccines.gov/basics/types
 
  • #5
Laroxe
Science Advisor
232
189
In vaccination campaigns there are quite a few advantages to using the live vaccine, it provides a far more effective immune response, particularly in the tissues of the gut and the fact that the virus is excreted for up to six weeks can mean it acts as a booster to other people who come into contact with the vaccinated person. The virus is weakened to the point it is incapable of causing disease but among the weakened virus there may be a few that have retained their virulence but these are not at a level that can establish a clinical infection.

So for the virus to become a problem it has to be repeatedly transmitted from person to person in a population in a way that allows the virus population in increase the percentage of potentially virulent organisms, this can only occur in populations with low vaccination rates and often requires other factors that impact on the levels of resistance.

Because the virus has to deal with so many challenges vaccine derived outbreaks tend to be very limited, the virus rarely if ever reaching the level of virulence seen in the wild virus. The individuals most at risk tend to be the very young or those who are immunocompromised. Outbreaks are managed by attempts to increase the vaccine coverage to interrupt transmission, though the presence of the disease may increase distrust of the vaccine.

There is a debate as to whether all polio vaccination should use the kill virus or subunit vaccines used in most countries, the problem is that while these carry no risk they are also far less effective.
 

Related Threads for: Viruses in Vaccines that can mutate and spread

  • Last Post
Replies
16
Views
7K
Replies
1
Views
3K
Replies
5
Views
3K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
2
Views
2K
Replies
1
Views
3K
Replies
2
Views
4K
Top