science

From a summary:

Drinking damages the liver and may make the body more vulnerable to infectious diseases, including sexually transmitted infections and tuberculosis.

Or from the review itself:

Infectious disease

The causal impact of alcohol on the four broad categories of infectious disease from the last Global Status Report on Alcohol and Health [1] has been confirmed in recent reviews [15, 16]. The main biological mechanism involves alcohol-induced liver dysfunction, which disrupts both non-specific innate and adaptive immune responses through acute and chronic alcohol consumption [80-84]. Lowered immune responses increase susceptibility to communicable diseases. More specific biological pathways are described in the references listed in Table 1.

Stop. Fucking. Your. Beer. Bottles.

Good point, highly likely the PhD students who authored this review were never taught about causation and correlation.