Fears about the spread of the H1N1 flu virus are affecting religious activities of Christians in a number of regions, especially in Britain, which two weeks ago announced 100,000 new cases.
British believers have had to introduce health measures for Communion services and in the use of holy water that some use to bless themselves upon entering churches.
Health authorities believe that the H1N1 flu pandemic is having a greater impact on Britain than on other European countries in part because Britain is a major international travel hub and because millions of Britons regularly spend their holidays abroad.
"Right now case numbers are roughly doubling every week, and that's a faster rate of growth than I might have anticipated," Professor Neil Ferguson, an epidemiologist at Imperial College London, told The Sunday Times.
Last Thursday, the top leaders in the Church of England wrote bishops to recommend that those presiding at Holy Communion suspend the administration of a shared Communion chalice, following advice from the Department of Health "to limit the spread of disease by not sharing common vessels for food and drink."
The archbishops of Canterbury and York said churches needed to "take into account the interests of public health during the current phase of the swine flu pandemic."
"Communicants ... need to be confident that the clergy and all assistant ministers follow the relevant guidance on hygiene," they added.
A day later, the World Health Organization's flu chief said the global H1N1 flu epidemic is still in its early stages, even though reports of over 100,000 infections in England alone the week before are plausible.
Keiji Fukuda, WHO's assistant director-general for Health Security and Environment, told The Associated Press that given the size of the world's population, the new H1N1 virus is likely to spread for some time.
WHO earlier estimated that as many as two billion people - nearly one-third of the world population - could become infected over the next two years.
It has been noted, however, that most people who get the new strain of flu - introduced to the world in April as the "swine flu" - only experience mild symptoms and don't need any treatment to get better.
Those more likely to get very ill, require hospitalization, and more likely to die are children (the younger, the higher risk), pregnant women, people 50 years of age and older, and people of any age with certain medical conditions - such as heart or lung disease, diabetes, and obesity - or those with weakened immune systems.
According to the U.S. Centers for Disease Control and Prevention (CDC), more than 70 percent of hospitalizations in the United States have been people with such underlying conditions.
Based on the experience of the 1957 flu pandemic, the CDC said the number of Americans who will die from swine flu over the next two years could range from 90,000 to several hundred thousand.
In comparison, about 20,000 deaths in the United States occur each year from the average flu or its complications, according to the National Institute of Allergy and Infectious Diseases (NIAID).