• Data shows that cases of RSV, flu and Covid are now all starting to rise in the US
• This is prompting fears of a ‘tripledemic’ hitting the health system this winter
• Doctors warn that other viruses are returning ‘with a vengeance’ in the US
• Immunity against them in the population has dropped raising infection risk 

The US could be thrashed by ‘tripledemic’ of viruses this winter as the knock-on effects of lockdown begin to bite.

Already cases of RSV — an infection that can be deadly in babies — are at their highest level in two years and the outbreak is months ahead of schedule.

The resurgence in RSV has caused a surge in pediatric hospital admissions with nearly 70 per cent of children’s hospital beds now filled by youngsters with respiratory bugs.

Experts have repeatedly told DailyMail.com lockdowns and measures used to contain Covid like face masks also suppressed the spread of germs which are crucial for building a strong immune system in children.

Meanwhile, flu cases have tripled in the past month and there are signs Covid is rebounding in 13 states.

Dr Scott Gottlieb, the former head of the Food and Drug Administration (FDA), said he expects this winter to be ‘more aggressive’ than normal because immunity to seasonal bugs is so low.

Immunity against more common diseases — like flu and RSV — has waned in the population as restrictions thwarted the spread of germs.

This led to children not building up a strong immune system, leaving them more exposed to seasonal pathogens.

A lack of infections over the last two years has also seen immunity wane in adults, as they have not been exposed to the diseases.

Dr Alpana Waghmare, an infectious diseases expert at Seattle Children’s Hospital told the New York Times: ‘We’re seeing everything come back with a vengeance.’

Dr Gottlieb told CBS ‘Face the Nation’ over the weekend that the Covid pandemic has ‘changed’ the circulation cycle for other viruses.

‘We’re seeing a peak in cases right now,’ he said.

‘This is not unlike the season last year, where we also saw an early peak.

‘In those cases, some people ascribe it to the fact that children have been somewhat removed from the circulating pathogen, so you don’t have as much immunity to the pathogen, so you don’t have as much immunity in the population generally.

‘So that’s changed the typical cycle for this virus.’

Typically the RSV season runs from mid-September to mid-November. But this year it began in August.

The virus, which causes mild, cold-like symptoms in most adults and older children, can be deadly for babies, according to the CDC.

In severe cases it can spread to the lower respiratory tract, causing pneumonia or bronchiolitis.

PCR-confirmed cases have now risen to their highest level since the pandemic began hitting 7,334 diagnoses in the latest week. 

For comparison, weekly cases did not rise above 5,000 last year. 

The surge has been blamed for an overwhelming rise in pediatric hospital admissions in recent weeks.

About 71 per cent of the nation’s 40,000 pediatric beds are currently filled, according to the Department of Health and Human Services, the most in two years.

Doctors have been raising the alarm over the virus saying they have ‘never seen’ this level of admissions for RSV among children.

Dr Juan Salazar, a physician in Connecticut, told CNN: ‘I’ve been doiung this a long time. I’ve been at Connecticut Children’s for 25 years, and I’ve never seen this level of surge specificallyfor RSV coming into our hospitals.’

Dr Mallory Davis, an infection expert at Helen DeVos Children’s Hospital in Michigan, added: ‘We are very full, and our census numbers are pretty high as we work through kind of figuring out how to accommodate all of the sick kiddos in the community.’ 

Parents are describing that the virus is leaving their babies struggling to breathe and with spiralling temperatures.

Mother and YouTube star Britanni Boren Leach said her five-week-old son had chest contractions and ‘crackles’ when he breathes due to the virus. He has been admitted to hospital for treatment.

‘My face probably says enough, but all of this has been extremely triggering for me,’ she said. ‘I typically don’t use that word, but I don’t know how else to describe it.’

This year’s flu season has also got off to an early start with cases beginning to rise in mid-September, rather than the October date anticipated. 

Data from the Centers for Disease Control and Prevention (CDC) shows there were 2,700 flu cases last week.

That was up by 31 per cent from the previous week, and triple the level a month ago when there were around 800.

But the figures represent a vast underestimate because the US does not routinely test for influenza in the same way as Covid.

Experts are on high alert about the virus after it made a resurgence in the southern hemisphere — which typically has a flu season that runs from April to October.

Australia suffered its worse flu season in a half-decade this year, with peak case rates reaching heights three times higher than usual. It also struck unusually early.

In New Zealand, flu cases this year returned to pre-pandemic normal after two years of stark decreases.

Covid cases in the US are now also starting to rise in some areas, with the national case tally plateauing at 78 cases per 100,000 people.

About 36,000 Americans are testing positive for Covid every day at present, similar to the previous week.

But some 15 states are now starting to see infections rise, in a warning sign that another wave could strike the US.

The sharpest upticks in a fortnight are in Hawaii, up 226 per cent, Kansas up 60 per cent, and Oklahoma, up 53 per cent.

Arizona, New Mexico, New Hampshire, Vermont, Nebraska, Maine, Ohio, Colorado, New York, Illinois, Indiana and Wisconsin are also seeing rises.

The surges are being driven by new ‘scrabble’ variants that are more transmissible than the Omicron that caused the wave last winter.

But there is no evidence that the virus has become more deadly, or more likely to cause disease as a result of infections.

The CDC said last week it was now monitoring BQ.1 — a more infectious version of Omicron — after the proportion of cases it was behind rose to one in five, double the level a week ago.

They are also keeping an eye out for XBB after it sent cases spiraling in Singapore, although there have only been a handful of confirmed cases in the US.

It comes amid a sluggish drive to get the updated Covid vaccine rolled out in the US.

Everyone over the age of five years who is already fully vaccinated is eligible for the updated shot, which is designed to target Covid variants.

Doctors say by raising the immunity level it could also help tackle the main variant currently in circulation — BA.5. 

But there is slower uptake for the jab.

The US has gone further than many other nations, which are only targeting over-50s — who are most at risk from Covid — in their booster drives.