With concern over the spread of the H1N1 flu, questions are being raised about its possible implications. For example, are people infected with HIV, the AIDS virus, or TB more susceptible to the flu than others?
Dr. Thomas Quinn, head of the Johns Hopkins Global Health Center, considers the potential threat from the flu outbreak.
"I think you use the right word: potential. We really don't know whether this will expand into a global pandemic. And WHO (World Health Organization) is preparing for that eventuality because you would not want to be unprepared should it occur. We really will have to monitor this on a day by day, hour by hour basis to see if it's going to expand rapidly to all countries of the world," he says.
Currently, he says H1N1 is "limited to a small number of countries. The actual number of cases is very small relative to what we ordinarily see with seasonal flu."
Seasonal flu is most prominent in the winter months, tailing off by April. However, H1N1 is a new virus for humans. It's unknown whether previous flu seasons provide any immunological protection against the new strain, but the typical flu vaccinations offered each year are not expected to offer any.
"Because of that uncertainty, we really have to gear up as if this could be a major, serious disease," he says.
Asked how many people on average die during an outbreak of seasonal flu, Quinn says, "In the United States, we usually see up to 30,000…deaths from a bad flu year. The people that are most susceptible to seasonal flu are the very young and the very elderly. Where new viruses come in is where we get concerned that it might hit the other age groups of the population."
He says that most of the cases of H1N1 have also been of the young and old "and it's those who had delayed, especially in Mexico, access to care till they were practically moribund."
The Johns Hopkins official says many in developing countries have poor access to health care. But so far, the developing world has been apparently been spared of any large number of cases. However, this could also be a result of the quality of surveillance systems, so time will tell.
Sub-Saharan African nations have high numbers of cases of HIV/AIDS, TB malaria and cancer, which weaken the immune system. Steroid drugs, given to treat some illnesses, can also weaken the immune system.
Quinn says, "The individuals who have HIV that are in more advanced stages of the disease are more susceptible. They are immune compromised and if unvaccinated are susceptible to any of the common Influenza A viruses. Obviously a lot of people in Africa are not vaccinated. The current vaccine we've been using in the US -- we do not believe that it is cross-protective against this new strain of the virus, anyway."
Health officials say everyone is believed susceptible to H1N1, and if infected, most could recover within a week.
"Those people with tuberculosis, especially XDR-TB (Extremely Drug Resistant TB), those people with HIV and…malaria...if they get flu…they will have more severe complications. And it could result in much more fatalities than we would normally have expected," he says.
Should H1N1 strike many developing countries, the same guidelines apply as they do in developed nations. Dr. Quinn says, "If you cough cover your mouth. If you sneeze cover your mouth. Wash your hands as often as you possibly can. Avoid close, intimate contact with people who are already sick from a respiratory infection. They may not know whether it's flu or not. They should make the assumption this could be flu and they should avoid direct contact, other than the healthcare providers, who should be wearing masks and gloves when they care for those people."