 GSK PLC LSE:GSK, NYSE:GSK shares have been slapped with a sell rating by UBS, which downgraded its recommendation as it sees two big long-term risks ahead. Admittedly, the risks are all the way out in 2027, when the Swiss bank worries that blockbuster shingles vaccine Shingrix will exhaust its catch-up patient pool in the US and HIV product dolutegravir faces patent expiry. 