Smallpox virus can spread between people who don’t know each other or people who get it during a person’s first visit to a doctor, according to a new study.
Researchers from the University of California, San Francisco found that people who had been vaccinated but didn’t have a history of getting the virus were more likely to be infected than people who did.
The study is published in the Journal of the American Medical Association.
The research was funded by the National Institute of Allergy and Infectious Diseases.
Smallpox outbreaks can occur when a person is infected with the virus or is exposed to the virus during a health care visit, or during travel, according a news release from the U.S. Centers for Disease Control and Prevention.
The virus can be transmitted through coughing or sneezing, or through a bite from an infected person.
For some people, the virus can cause pneumonia or death.
The new study was led by Dr. John F. Hochberg, a professor of microbiology and immunology at the UC San Francisco School of Medicine.
The researchers collected data from a group of about 2,000 people who were vaccinated with the smallpox vaccination.
All of them were followed for a year to see if they got the virus.
They also collected the virus samples from people who didn’t get the vaccine, or for people who hadn’t been vaccinated.
About half of the people who received the small-pox vaccine and didn’t know their vaccination status had received a new smallpox shot during the year before the survey.
About two-thirds of the participants didn’t remember the vaccine being given to them.
The remaining people who reported getting the vaccine and were infected were more than twice as likely to have become infected.
The vaccine is given by a person who has the small virus and who has a sore throat or a sore nose.
About 80% of the time, the person gets the vaccine after a visit to the doctor or the dentist.
The second half of people who got the vaccine were more at risk of contracting the virus, because they were less likely to get the sore throat after a doctor’s visit, for example.
They were also more likely than those who didn`t get the small vaccine to be exposed to people who have been infected.
Those who received a second dose of the vaccine had higher levels of antibodies against the virus than the other group.
The antibodies against smallpox were detected in their saliva, blood and urine.
The team also found that the people with the highest levels of the antibodies had the lowest rates of developing new small-cell pneumonia and the most frequent hospitalization with pneumonia, the new study found.
The findings are likely to help scientists figure out how to prevent new infections and protect against new infections.
The CDC recommends the vaccination of people between the ages of 15 and 59.
The small-ball vaccine was approved in the United States in 1968 and has been used in the U and Canada since the mid-1990s.
In recent years, there has been an increase in the number of people being vaccinated in the developed world, and many countries have started rolling out vaccines for people aged 50 and older.