immunity debt noun [U]
UK /ɪˈmjuː.nə.ti.det/ US /ɪˈmjuː.nə.t̬i.det/
the situation where people have been avoiding exposure to the Covid-19 virus and have therefore not developed immunity to other viruses, causing larger, more serious outbreaks of illness later

New Zealand hospitals are experiencing the payoff of “immunity debt” created by Covid-19 lockdowns, with wards flooded by babies with a potentially-deadly respiratory virus, doctors have warned … The “immunity debt” phenomenon occurs because measures like lockdowns, hand-washing, social distancing and masks are not only effective at controlling Covid-19. They also suppress the spread of other illnesses that transmit in a similar way, including the flu, common cold, and lesser-known respiratory illnesses like RSA.
[theguardian.com, 8 July 2021]

pingdemic noun [C usually singular]
/ˌpɪŋ.ˈdem.ɪk/
the situation where a very large number of people have received an alert on their phone telling them that they must self-isolate as they have been in contact with someone who has Covid-19, causing problems for businesses and services as they cannot go to work

With case numbers rising sharply in England as restrictions are lifted, the country has seen what has been dubbed as a “pingdemic”, with hundreds of thousands of people told to stay at home after being deemed to have been in close contact with someone who has tested positive for Covid-19.
[standard.co.uk, 28 July 2021]

vaccine nationalism noun [U]
/ˌvæk.siːn.ˈnæʃ.ᵊn.ᵊl.ɪ.zᵊm/
the situation where a country tries to buy supplies of a vaccine before or instead of other, usually poorer, countries

This “vaccine nationalism,” in which countries prioritize their domestic needs at the expense of others, may have helped accelerate efforts to develop such drugs, but it is already showing its limits. With wealthy countries claiming the lion’s share of prospective doses for themselves, and with global efforts to equalize vaccine distribution facing enduring unilateralism and limited resources, a coronavirus vaccine returning the world to something resembling “normal” could take considerable time—perhaps even longer than it needs to.
[theatlantic.com, 8 December 2020]

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