New Zealand hospitals are experiencing payment of the “immunity debt” created by the Covid-19 shutdowns, with wards flooded by babies with a life-threatening respiratory virus, doctors warned.
Wellington has 46 children currently hospitalized for respiratory illnesses, including respiratory syncytial virus, or RSV. Some are babies and many receive oxygen. Other hospitals are also seeing an increase in cases that are depleting their resources, with some surgeries delaying or turning game rooms into clinical spaces.
RSV is a common respiratory disease. In adults, it usually only produces very mild symptoms, but it can cause extremely ill or even fatal young children. The size and severity of the New Zealand outbreak is likely fueled by what some pediatric doctors have called an “immunity debt,” where people do not develop immunity to other viruses suppressed by the Covid shutdowns, causing cases explode in the future.
Epidemiologist and public health professor Michael Baker used the metaphor of wildfires: If a fire or two has passed, there is more fuel in the ground to fuel the flames. When a fire finally hits, it burns much fiercer. “What we are seeing now is a lot of accumulated susceptible children who have missed exposure, so now they are seeing it for the first time,” Baker said.
The phenomenon of “immunity debt” occurs because measures such as lockdowns, hand washing, social distancing, and masks are not only effective in controlling Covid-19. They also suppress the spread of other similarly transmitted diseases, including the flu, the common cold, and lesser-known respiratory illnesses like RSA. In New Zealand, last winter’s run-ins led to a 99.9% reduction in flu cases and a 98% reduction in RSV – and nearly eliminated the spike in excessive deaths New Zealand typically experiences during winter.
“This positive short-term side effect is welcome, as it avoids an additional burden on the health system”, a group of French doctors wrote in a May 2021 study on immunity debt. But in the long run, it can create problems of its own: If bacterial and viral infections don’t circulate among children, they don’t develop immunity, leading to larger outbreaks later in life.
“The lack of immune stimulation … induced an” immunity debt “that could have negative consequences when the pandemic is under control and [public health intervientions] get up, ”the doctors wrote. “The longer these periods of ‘low viral or bacterial exposure’, the greater the likelihood of future epidemics.”
New Zealand has reported nearly 1,000 RSV cases in the past five weeks, according to the Institute for Environmental Science and Research. The usual average is 1,743 for the entire 29-week winter season. Australia is also seeing an increase, with overcrowded Victoria hospitals also affected by unusually high rates of RSV.
Spikes like the current outbreak don’t necessarily mean the country will have more RSV cases overall, says Baker; all cases may be grouped together, rather than spread out over several years. But even that can cause major problems. “If you get a major spike, it can overwhelm your healthcare system or put real pressure on it, which we’re seeing with RSV,” Baker said.
The current outbreak is already affecting New Zealand hospitals. At Middlemore Hospital in Auckland, a playroom has been converted into a clinical space with 11 cribs for special care babies. Health boards in Auckland and Canterbury have postponed surgeries to divert resources to children’s wards. Several hospitals have asked children under the age of 12 not to visit, to try to prevent the spread of the virus. John Tait, medical director of the Wellington area district health boards, said the region had 46 hospitalized children, including two in intensive care. Those numbers were “continually changing as patients are discharged and others are admitted,” he said.
People generally experience near-universal exposure to RSV as children, Baker said, and most are exposed in their first year of life.
“If you remove that exposure over a period of time, you will have a larger cohort of unexposed children, and therefore as you can see that we are happening right now, you can sustain a much larger outbreak when they are finally exposed to the virus. “
While RSV is a common cause of winter hospitalization for children, older people and people with weakened immune systems are also vulnerable. New Zealand Health Director Dr Ashley Bloomfield said he was “certainly concerned about the sharp increase in RSV cases.”
“We had very little RSV last year,” he said. “There is some speculation that [the current outbreak] It may be compounded in part by the fact that we didn’t have any last year and therefore there is a larger group of children who are susceptible. “