Private research is highly based on coming up with selling points for pharmaceutical products rather than on clinical research that makes it possible to fully understand the safety of those products. When data secrecy is imposed, and the data are produced by companies and then published in medical journals, the data that are going to be published are carefully selected. The trend is to opt for those data that better support the sales pitch they want to make to doctors.
Right now, more than 85% of basic research is currently funded by the public. So it is essentially public, but it is geared towards commercialization by large corporations.
In terms of clinical research, the major public trials carried out in the United States by the National Institutes of Health have largely made it possible to have an objective and neutral idea of the benefits of a product as opposed to its risks. Sometimes, major clinical trials can set things straight in terms of whether a product is actually good or not.