Omicron’s effects hit older people harder

A third of daily Covid cases are now in people aged over 50, prompting concern the virus could find it easier to infect more vulnerable demographics.

The Omicron outbreak hit the young first. When it was at its peak in late February, 60% of cases were in ages 10-30 and 10% in over-50s.

But since March, as case numbers have slowly dropped, the proportion of cases in over-50s has continued to slowly rise. On Thursday, over-50s made up 34.4% of daily case numbers.

Overall case numbers have remained stable in over-50s since April and have ever-so-slightly increased in over-80s and 90s.

Last week saw the highest single day of over-90s infections since the pandemic began – 71 on Wednesday.

Omicron’s impact on health increases steeply with age, known colloquially by some as the ‘‘ski jump’’.

Latest June data, from the Centres for Disease Control and Prevention in the US, shows people aged 50-64 are 25 times more likely to die of a Covid infection than someone aged 18-29. Those over 85 are 330 times more likely to die.

University of Otago public health professor Dr Michael Baker said there could be many reasons for the outbreak starting to skew towards older age groups.

Baker said that because over50s had succeeded in keeping away from the virus early in the outbreak, they were now the group that had the least immunity to it.

Experts have feared pandemic fatigue could mean the elderly gradually moving out of selfimposed restrictions and into more risky social circles. A simple visit from family members could be all it took, given how widespread the virus was, Baker said.

‘‘There is no question, I think, that schools have resulted in huge transmission and also reinfections.

‘‘They are taking the infection home to their families.’’

The Ministry of Health’s advice is for people not to test for 90 days after an original positive test result, even if symptoms return.

‘‘If you are at low risk of severe illness, stay home and recover until 24 hours after you no longer have symptoms. You do not need to take a rapid antigen test (RAT),’’ its website says.

Vulnerable people are instructed to contact their doctor or Healthline.

Baker said the ministry’s advice, which he felt was problematic as it might miss reinfections, could be part of the reason that younger people were no longer reporting as many positive RATs.

‘‘We have got over 1.2 million people now who have tested positive, almost all through RATs, and they are at a lower risk for a period, of course. But they won’t be testing even if they are getting reinfected, so that advice is maybe contributing to this trend.’’

Baker said if Omicron started to find more of a foothold among those most vulnerable to it, it would be a big concern for our health system.

‘‘If it is shifting to older age groups, that is going to be a real problem. The infection-fatality rate goes up hugely once you hit 70 and 80. But the risk is still there for younger people and there are still the potential consequences of long Covid that we don’t have quantified. It means it really is still important to try to avoid infection,’’ Baker said.

Second booster shots for people deemed at most risk of getting seriously sick from Covid-19 are likely to be rolled out next month.

The Government has introduced a bill to amend the Medicines Act which will enable voluntary booster doses to be administered without a prescription. The changes will make it easier for people without access to a general practice doctor to get second booster doses and will apply to about 850,000 people at high risk of getting very sick from Covid-19.