Hello, I am glad to hear that your son got the HPV vaccine. It is fairly recent that the vaccine is recommended in both men and women to prevent the spread of HPV, as the vaccine works very well against some strains of this virus. The vaccine he most likely received is called Gardasil and you are correct that it comes in a series of three. Although this sounds like a difficult situation, my recommendation would be to obtain formal documentation about the vaccines, as the vaccine really works best after you receive all three shots. You could also get his primary care doctor
involved, as they may be able to advocate for insurance covering the next two shots if you are quite sure he didn't receive them. I would advise you to speak to his doctor about this. That being said, studies have shown that you do have some immune response (meaning that your body makes defenses against the virus) after just the first dose of the vaccine. Given that he hasn't had the whole series, and just for general health, you or someone else who is comfortable doing so, should speak to your son about having protected sex always. Condoms are the best protection against sexually transmitted infections, and your son should use this regardless.