Stress and unhappiness may affect the body in ways not yet understood.
The sick may also be more likely to become socially isolated.
The government has done much to reduce stigma around mental ill health: the NHS repeatedly encourages people to consider their mental state (though it is unable to provide talking therapy to many who need it).
Mr Andrew, hopes the same thing will happen with loneliness.
That seems unlikely because admitting to loneliness can seem to reflect on a person in painfully personal ways.
Depression can strike anyone; no one wants to be thought of as love-less or friendless.
Having public figures talk about loneliness would help.
Alluding to specific causes is a useful start.
That is why Mr Andrew talks about growing up gay, and feeling alone.
Speaking about loneliness might also encourage people to consider that others are suffering.
Small interactions are crucial, says Professor Qualter.
With this in mind the government has funded a few initiatives.
NHS receptionists are being trained to identify lonely people.
Not every harried staffer considers that the old man who arrives hours early for his appointment might not have seen anyone in days.
People who sign up for such courses seem likely to be empathetic already, though.
Lesley Emongo, a receptionist in Peterborough, says the training gave her strategies for dealing with the many lonely patients she encounters.
The ons’s standard questions for surveys may be the most useful intervention.
It hopes academics and charities will measure loneliness in the same way so “we will build a much better evidence base more quickly”.
Professor Qualter says there is no evidence yet that any interventions have been effective.
This may be because the things that make people lonely—such as poverty or disabilities—also make them hard to reach.
The professor would like to see more ambition, including designing public services with spaces that encourage congregation.
Austerity brought brutal cuts to many places, like youth clubs, where people once gathered.
A loneliness strategy is unlikely to make up for those losses.