"The overall age-adjusted vaccine effectiveness against infection for all New York adults declined from 91.7% to 79.8%." - https://www.cdc.gov/mmwr/volumes/70/wr/mm7034e1.htm?s_cid=mm...
"Two doses of mRNA vaccines were 74.7% effective against infection among nursing home residents early in the vaccination program (March–May 2021). During June–July 2021, when B.1.617.2 (Delta) variant circulation predominated, effectiveness declined significantly to 53.1%." - https://www.cdc.gov/mmwr/volumes/70/wr/mm7034e3.htm?s_cid=mm...
"The efficacy figure, which is based on an unspecified number of people between June 20 and July 17, is down from an earlier estimate of 64% two weeks ago and conflicts with data out of the U.K. that found the shot was 88% effective against symptomatic disease caused by the variant." - https://www.cnbc.com/2021/07/23/delta-variant-pfizer-covid-v...
"“As seen in real world data released from the Israel Ministry of Health, vaccine efficacy in preventing both infection and symptomatic disease has declined six months post-vaccination, although efficacy in preventing serious illnesses remains high,” the companies said in a written statement. “These findings are consistent with an ongoing analysis from the Companies’ Phase 3 study,” they said. “That is why we have said, and we continue to believe that it is likely, based on the totality of the data we have to date, that a third dose may be needed within 6 to 12 months after full vaccination.” ...... Executives from Pfizer and BioNtech have repeatedly said people will likely need a booster shot, or third dose, within 12 months of getting fully vaccinated because they expect vaccine-induced immunity to wane over time. They also said it’s likely people will need to get additional shots each year." - https://www.cnbc.com/2021/07/08/pfizer-says-it-is-developing...
So, while it's true that the effectiveness wanes, the same articles also point out that it is still effective at preventing severe hospitalization. If you're vaccinated, you're more likely after 6 months to get COVID anyway, but you are much less likely to be sent to the hospital or die.