How can one avoid getting these infections

Frankly, there is very little chance of avoiding these. Though several vaccines have been developed and successfully tested, particularly in the USA where these infections, when they have occurred have lead to severe epidemics and fatalities, largely the causative viral strains are unknown and having them once does not guarantee any immunity from further infections, especially in the sub-continent. The best methods to be followed are staying away from persons who are sneezing and coughing, particularly during season-change and having a sound body constitution helps. Try not to use tissue papers and handkerchiefs of the suffers and dispose or wash them as hygienically as possible.