Scientists have finally put their finger on it: Picking your nose isn’t just a social flub, it also might be bad for your health.

British researchers recently said they have shown that the pneumonia-causing pneumococcus bacteria can be transmitted between hand and nose. They say they are the first to prove that it isn’t just the inhalation of airborne droplets that spreads the bug.

Researchers enlisted volunteers to prove the point. One group sniffed their hands after they were splashed with water containing a harmless dose of the bacteria. A second group sniffed air-dried bacteria on the back of their hand.

Two other groups had the toughest job. They were tasked with either picking or poking their noses after fingers were exposed to wet or dry bacteria.

The researchers later tested the volunteers’ noses for the pneumococcus. The wet poke and wet sniff groups had the highest rate of transmission. But all groups, wet or dry, tested positive.

Research also showed that a little nose rubbing — with the back of the hand — also spreads the bacteria.

To researchers, these findings underscore the importance of good hygiene to prevent infection, including rigorously washing hands.

It gets complicated with kids. Scientists say the presence of the bacteria sometimes inoculates them from pneumonia later in life. So, it is unclear if reducing the spread of pneumococcus is always best for them. Even so, hand washing, researchers say, is important if children are in contact with those especially susceptible to pneumonia, such as the elderly.

After all, as many parents can attest, it isn’t realistic to keep a child from picking or rubbing their nose when the urge hits them.