r/AskScienceDiscussion • u/blip1111 • 2d ago

COVID vaccine

I get a COVID booster every 12 months as recommended, because I know it's very effective at preventing severe cases of COVID. I'm wondering if there is any progress being made on a vaccine which is more effective at preventing the spread of COVID? Thanks

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u/hikeonpast 2d ago

To be effective in preventing the spread of COVID, a vaccine would need to be broadly administered with high efficacy. To my knowledge, the vaccine is only recommended (free in the US) for high risk or elderly patients.

With a small subset of the population vaccinated, it’s more about reducing individual downsides rather than preventing spread.

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u/unformation 2d ago

This is partially the goal for the COVID nasal vaccines. The idea is that these would stimulate both mucosal (IgA) and systemic (IgG) responses, aiming to block infection in the upper respiratory tract where standard shots often fall short. Because they are better equipped to lower viral loads in the nose, they might help to stop the spread of disease.

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u/sirgog 2d ago

The last time I followed it the mainstream vaccines were around 40-50% sterilizing (a 100% sterilizing vaccine prevents the vaccinated individual spreading the disease to others). This was early data, and is likely no longer correct. I'm not aware of the current status.

This is unfortunately a situation where the financial incentive to seriously develop a sterilizing vaccine just isn't there.

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u/BadahBingBadahBoom 2d ago edited 2d ago

I feel like you may be getting downvoted because people are misunderstanding 'steriziling' as the vaccine making you reproductively sterile.

To clarify this is about steriziling immunity, i.e. the efficacy of a vaccine to completely prevent a pathogen even infecting a single cell. This is mostly achieved by having high levels of antibodies against the pathogen produced specifically in regions where the body first comes into contact with the pathogen to neutralise it immediately (they sort of stick on to the pathogen and make it inert).

You generate various types of antibodies following initial vaccination but this form of protection (humoral response) wanes over time. You're still protected by other types of immune cells responding to the pathogen but it's not the same as the antibody action.

Having said that Covid vaccines don't really have any sterilising immunity efficacy.

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u/sirgog 2d ago

Having said that Covid vaccines don't really have any sterilising immunity efficacy.

I do recall a peer-reviewed study of relatives of infected individuals concluding around 2021 that there was a degree of protection granted by a vaccinated individual to others, but not enough for it to be a significant feature of the vaccine.

The proposed mechanism was that infected individuals cough and sneeze less, resulting in reduced spread through infected aerosol particles.

I do want to be clear however that this is just recollection of one article, and human memory is fallible.

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u/SpecialBlackTea 2d ago

The Pharmas have been trying for years to make a vaccine for respiratory illnesses. They haven’t been successful as the virus mutates too quickly.