Please explain why people with asthma and people who smoke cigarettes are recommended to be vaccinated against pneumococcal disease?

In 2008, ACIP reviewed evidence indicating that asthma is an independent risk factor for pneumococcal disease among adults. ACIP also reviewed evidence demonstrating an increased risk of invasive pneumococcal disease among smokers. Consequently, ACIP includes both asthma and cigarette smoking as indications for pneumococcal vaccination among adults age 19 through 49 years. People with these conditions should receive either a single dose of PCV20 or PCV21 alone, or a dose of PCV15 followed one year later by PPSV23. If they have already received PPSV23, but have not had a conjugate vaccine, they should receive a single dose of a recommended pneumococcal conjugate vaccine (PCV15, PCV20, or PCV21) at least one year following their dose of PPSV23.