I apologize for taking so long but I wanted to compose a very clear and detailed explanation. I know you may not like this answer, and that is ok. Many people are mislead into believing there is a cure for the flue or flue preventive after exposure. While it is possible that a flue vaccine may prevent development of the flue after exposure, it is not common, especially after three days.
thank you for clarifying. If your son had stomach flu, you really are too late to prevent its occurance if you have been infected. The incubation period is within 3 days.
the normal prevention is to avoid contact by the following primary ways:
1. hand washing.
2. Handling the sick person's bedding and clothing with gloves while wearing a mask, and washing them right away as they are used.
3. Cleaning the sick person's bed linens and even the bed itself (mattress, rails and head and foot boards).
Most people do not go to this level in their homes.
Since you are all ready exposed, and not showing symptoms, it is difficult to determine if you are infected.
There is no medication to prevent the flue that you can take after exposure that will be effective.
Many people belive that there are medications on the market to prevent flue or to cure the flue, after they are exposed,but this is not true. Such over the counter medications have boasted in the past that they can cure the flue, but the FDA got involved.
now they only admit to releiving the severity of the illness.
Vitamin C will strengthen the immune system to help relieve the seriousness.
Zinc is known to affect the viability of the flue virus. BUT is does not prevent it.
This means you have to focus on preventing the N & V that will accompany the disease should you come down with it on your trip.
Over the counter anitemetics is limited to Kaopectate and peptobismal (or other brands of the same preperations).
A better choice may be a presription medication of Promethazine HCl or similar drug that can act on the nervous system to eliminate vomiting all together. But these may not be a wise choice because of potential side effects.
While it will not eliminate totally the feeling of vomiting, you can best reduce the chances of vomiting by reducing stomach contents.
If you eat very little or limit yourself to clear licquids, then you will not actually vomit, even though you may get some gag reflex.