In some cases, these vaccines use epitopesâthe very specific parts of the antigen that antibodies or T cells recognize and bind to. Because subunit vaccines contain only the essential antigens and not all the other molecules that make up the microbe, the chances of adverse reactions to the vaccine are lower.
Tornadoes occur in many parts of the world, including Australia, Europe, Africa, Asia, and South America. Even New Zealand reports about 20 tornadoes each year. Two of the highest concentrations of tornadoes outside the U.S. are Argentina and Bangladesh.
More tornadoes strike in the part of the United States that lies between the Appalachians and the Rockies than anywhere else on earth, but tornadoes have been observed on every continent except Antarctica. Tornadoes called waterspouts occur over water but do not seem to form from supercells.