From between the bars of his iron prison, the lion-tailed macaque snaked out a simian hand for my brother. He was reaching for his friend. The monkey's name was Henry and he lived in Kolkata zoo where one of my brothers, then 16, worked as a volunteer in the mornings.

A kinship blossomed, a routine developed. At the sight of my brother, Henry would bound across the cage, clutch the bars and expect his back to be rubbed in an act called grooming. Then my brother would turn his back to the cage and Henry would repay the favour by picking through his hair. No confirmation exists of lice being found. This mattered to me since I shared a bed with one of them.

I thought of this last week because as cities yawn and open slowly for business, like fidgety giants awakening from long slumbers, I wondered about touch and what it means to us. Grooming a monkey might still be fine, but what about us? What happens in a world where the casual tap, pat, nudge, embrace of another human may not be welcome? Will we stop reaching for each other? Will we flinch from what was once natural? It would be like temporarily amputating an ancient instinct.

Touch, it is argued, is the first sense to flower and certainly when we are born, we are often placed naked on our mother's bare chest. Two weeks or so after my granddaughter was born, on an unforgettable winter afternoon, my daughter gently placed her on my chest against my skin. There we sat, quietly, wrapped in a blanket, fastened together forever.

Touch is its own kind of glue and, eventually, it develops into a vast unspoken language. We touch to console, to make a point, to flirt, to reassure. As my father - as tactile a man as I have ever met - aged, he would reach for my mother's hand every time she left a room.

Touch binds, it is used to poke a chest in argument, alter a friend's direction in a mall, bless a child and explore the contours of the planet. In her 1933 essay in The Atlantic Monthly, Helen Keller, deaf and blind, wrote: "I feel the delicate symmetry of a leaf. I pass my hands lovingly about the smooth skin of a silver birch, or the rough, shaggy bark of a pine."

If touch is a language in itself, then there is no real substitute for it. You cannot semaphore sympathy to a colleague who has lost a job. You can't lean on words as you do on a friend's shoulder. There is nothing sometimes to be done for the dying except for the social worker to hold a frail, fluttering hand. But now, abruptly, the profound has become risky.

Distance is not a remote idea any more, it has a specific measurement. One metre. We are being warned away from proximity and so, at airports, do we bid farewell from afar and, at home, must we deftly avoid an old visiting uncle who tells long stories while holding our hand? Will we become unkind?

Some things we will still touch because we will convince ourselves that tugging a book from a shop shelf can't be resisted. What is a book's worth, after all, if it can't be held close and inhaled? As Susan Orlean wrote evocatively of bookstores in The Library Book: "I loved the crack of a newly flexed spine, and the way the brand-new pages almost felt damp, as if they were wet with creation."

For some, negotiating this altered world might be trickier than others. Sophie Soon, 22, a competitive para-swimmer with a degree in cheerfulness, wanders this city with a guide dog or a white cane. "For a lot of blind people," she says "our hands are our eyes."

She uses public transport and touching is an essential part of her guidance system. "I generally touch doors, escalator handles to check if they're going up or down and lift buttons." And, she says with a laugh, clothes as well to feel the material.

"I don't think I have much of a choice now, I still have to touch," she says, but she will go armed with hand wipes, hand sanitiser and sound tactics. She will try to wander through places she knows rather than unfamiliar ones. Asking for assistance, after all, often means taking a stranger's arm.

Cultures will negotiate this terrain with unequal ease, for we all measure personal space with a different ruler. Three years ago, The Washington Post reported that researchers had conducted a study and found, for instance, that "in Saudi Arabia, people stand farther from their friends than Argentinians do with strangers. Hungarians want loved ones and strangers at arms length, or at least 75cm". Comfort is a precise business.

The Japanese are fine because they bow at a conservative distance, but the Maori practise the hongi, a greeting which involves pressing noses together and is discouraged during the pandemic. Indians, from a crowded land that is oblivious to personal space, can be huggers and claspers of a formidable kind. Yet, I have a friend who is an anomaly: She so dislikes intimacy that she hugs sideways. The no-touching of the pandemic may be her finest moment.

Human beings will muddle through, they will hesitate, recoil and hold onto caution, they will struggle and sometimes make compassionate choices. They might hold close a weeping friend because it seems more important. They will sit close during protests, as they are doing in America, because greater than any personal risk is a cause which touches them deeper.

Life will continue, work forces will adapt and even Romeos will have to adjust. Once, rather overcome, he said of Juliet:

"See, how she leans her cheek upon her hand!

O, that I were a glove upon that hand,

That I might touch that cheek!"

Now, we'd say: Sorry pal, easy on the touching. Blow her a kiss and go home quietly. Then wash your hands in the prescribed manner for 20 seconds.