By Luke Andrews & Caitlin Tilley

Doctors in parts of Massachusetts and Ohio are reporting a spike in child pneumonia cases similar to the outbreak spreading in China and parts of Europe.

In Warren County, just 30 miles outside Cincinnati, there have been 142 pediatric cases of the condition — dubbed 'white lung syndrome' — since August, a figure health officials there described as 'extremely high'.

'Not only is this above the county average, it also meets the Ohio Department of Health definition of an outbreak,' the county's health department said Wednesday.

Meanwhile, in western Massachusetts, physicians are seeing 'a whole lot' of walking pneumonia, a milder form of the lung condition, which is being caused by a mixture of bacterial and viral infections.

Neither outbreak is being caused by a novel pathogen and not all of the pneumonia cases are being caused by the same infection. Experts say a mixture of several seasonal bacterial and viral bugs are hitting at once, putting pressure on hospitals.

It has raised fears that the outbreak that has overwhelmed hospitals China could hit the US this winter. Several European countries are battling similar crises.

But a source at the Centers for Disease Control and Prevention (CDC) said that, nationally, 'nothing is out of the ordinary' in the data.

Dr Amesh Adalja, an infectious disease expert from Johns Hopkins University in Maryland, said: 'I would caution against extrapolating one Ohio county to a country of 330million people.'

But he would not be entirely surprised if 'some places in the US are above baseline' this year, as it appears several bacterial and viral infections are rebounding post-Covid.

An 'ongoing investigation' is underway in Ohio into what is triggering the wave of illness.

Patients in the county - which is home to around 200,000 people - have tested positive for mycoplasma pneumoniae, a bacterial lung infection for which some antibiotics are useless, adenovirus, a normally benign respiratory infections, and strep.

The average age of patients is eight, though some are as young as three.

There are several theories, one of which is that children's immunity has been weakened by lockdowns, mask-wearing and school closures during the pandemic — leaving them more vulnerable to seasonal illnesses.

Bacterial respiratory infections usually flare up every five years, normally as people are recovering from a wave of flu or other viral illnesses.

Most infections are mild, but those who have recently recovered from a respiratory infection are at higher risk.

In a release from the Warren County Health District, officials said: 'We do not think this is a novel/new respiratory disease, but rather a large uptick in the number of pneumonia cases normally seen at one time.'

It added: 'As we approach the holiday season, when many of us will be gathering together with family and friends, please remember to take necessary precautions to protect your health.

'Wash your hands, cover your cough, stay home when ill and stay up to date on vaccines.'

Doctors say patients are mostly suffering from a fever, cough and fatigue.

It is unclear if any deaths have resulted from the illness and officials have not responded to requests for more information.

In Massachusetts, doctors say the main issue is RSV, a respiratory virus that kills more than 10,000 Americans each year, mostly young children and the elderly.

Dr John Kelley, from Redwood Pediatrics in East Longmeadow, told Western Mass News: 'This is the season for RSV and we're seeing a whole lot of it… a lot of kids with upper viral respiratory infections, cough, runny nose, some fevers and the thinking with RSV is that it can cause lower viral respiratory infections, so they get spread to your lungs.'

He said 80 percent of the kids with walking pneumonia develop the infection as a result of first having RSV, while the remaining 20 percent of the cases are usually attributed to bacterial infections like mycoplasma pneumoniae.

Dr Adalja believes the pneumonia outbreaks cropping up around the world could be due to the 'cyclical' nature of mycoplasma.

'Mycoplasma goes through epidemic cycles every few years and that may be what's occurring globally at the moment.'

He said China may be getting hit by a double-whammy of viral and bacterial infections. China is entering its first winter without pandemic restrictions, and is reporting surges in Covid, flu and RSV as well as mycoplasma.

The US, Canada and Europe — where Covid restrictions were lifted earlier — were hit by massive upswings in those viruses last year.

'So what's happening in China makes sense', Dr Adalja said, adding: 'Last year we were dominated by so much Covid, flu and RSV when we opened up.'

He said he thinks this year's winter outbreak will be 'less severe' that last year's, when thousands of children were hospitalized with RSV and flu.

But Dr Adalja admitted that lockdowns have contributed to the emerging global phenomenon.

'When children are born they haven't experienced any infectious diseases so more of them you have in population so lower threshold for outbreak to start.

'That group of children born provide new people for illnesses. The pandemic allowed the number of these susceptible people to build up over years.'

In Ohio, the county was first alerted to the spike after schools said they were recording more children out sick than normal.

The 142 cases were reported to the county from multiple school districts across their area. There are 12 school districts in Warren County, Ohio.

Speaking to local reporters, Warren County's medical director Dr Clint Koenig said: 'We have seen hospitalizations [for child pneumonia] tick up in the last couple of weeks so we do ask parents to be vigilant.

'Our school districts have called in starting roughly in August, but really picking up in mid to late October.

'We've also been noticing a lot of cases of kids being absent and the resulting diagnosis being pneumonia.'

A source at the Centers for Disease Control and Prevention (CDC) said their data showed childhood pneumonia levels in other states were following 'seasonal trends'.

'Nothing is flagging out of the ordinary, but we are continuing to monitor,' they said.

Mycoplasma pneumoniae normally causes a mild flu-like illness, sometimes called 'walking pneumonia'. Cases are most common in younger children.

Some antibiotics, such as penicillin, have no effect.

Strep also normally causes a mild illness and tends to leave patients with sore throats. It's more common among those aged five to 15 years old.

And adenovirus, which has also been detected in patients in Ohio, causes symptoms similar to the common cold.

It was thought to be one of the viruses driving a spike in childhood hepatitis cases last year in children in the US.

Dr Scott Roberts, an infectious diseases expert at Yale School of Medicine, Connecticut, said the uptick in cases was likely still being driven by weakened immunity in children.

He said: 'This is probably a recurrence of known pathogens that are hitting us a bit harder because of low immunity to them.'

He suggested children's immune systems could still be suffering from the effects of Covid restrictions which blocked their exposure to 'good germs' for building immunity. He also pointed out that immunity wanes over time.

It comes after the Netherlands and Denmark also said they were recording mysterious spikes in pneumonia cases, many of which are being attributed in part to mycoplasma.

CDC director Dr Mandy Cohen said while testifying in Congress today that the uptick in respiratory illnesses in China was not down to a novel pathogen.

Dr Cohen told the House Energy and Commerce Subcommittee: 'We do not believe this is a new or novel pathogen.

'We believe this is all existing [pathogens] — meaning Covid, flu, RSV, mycoplasma. But they are seeing an upsurgence.'

The CDC has been coming under pressure to reveal everything it knows about the China pneumonia outbreak, with members of Congress sending a letter to the agency yesterday.

China has been recording a surge in childhood cases of pneumonia since May which only came to light last month.