Nearly two years ago, as the COVID pandemic disrupted life around the world, other infectious diseases were in decline. Now, with the world rapidly dismantling the measures put in place to slow the spread of COVID, viral and bacterial nuisances that were on hiatus are back — and behaving in unexpected ways.
Consider what we saw recently.
The past two winters have been among the mildest flu seasons ever, but hospital admissions have been up in the past few weeks – in May! Type 41 adenovirus was previously thought to cause fairly harmless episodes of gastrointestinal disease, and may cause acute hepatitis C in healthy young children.
Respiratory syncytial virus, or RSV, an insect that usually causes illness in winter, caused outbreaks among children last summer and early fall in the United States and Europe.
Watch: With the outbreak, what is monkeypox and how does it spread?
Now monkeypox, a virus generally found only in West and Central Africa, is causing unprecedented outbreaks in more than a dozen countries in Europe, North America, the Middle East and Australia, with the UK alone reporting more than 70 cases. Tuesday.
These viruses are no different than they were before, but we are. For one thing, due to COVID restrictions, we’ve had less immunity lately; As a group, more of us are at risk right now. Experts suggest that this increase in susceptibility means that we may see some … imbalance as we work toward a new post-pandemic equilibrium with the insects that plague us.
Bigger waves of disease can strike, which in some cases can lead to problems we didn’t know were causing these bugs. Diseases can spread at times or in places where they would not normally.
“I think we can expect some of the presentations to be out of the ordinary,” said Peter Broden, Professor of Pediatric Immunology at Imperial College London. “Not necessarily really intense. I mean, it’s not a doomsday projection. But I’m thinking a little bit out of the ordinary.”
Marion Koopmans, chief of virology at Erasmus Medical Center in Rotterdam, the Netherlands, said she thinks we may be facing a period when it’s hard to know what to expect from diseases we thought we understood.
“I think it’s possible,” Koopmans said.
She suggested that this phenomenon, perturbing the natural patterns of infection, may be particularly evident for diseases where children play an important role in the spread of insects.
Young children are usually germ magnets and bactericides. But their lives changed profoundly during the pandemic. Most of them went for long periods without going to nursery school or school. Many of them had much less exposure to people outside their homes, and when they met others, these people may have been wearing masks.
Babies born during the pandemic may have entered the world with few antibodies passed on to their mothers in the womb, said Hubert Nesters, professor of clinical virology, because those mothers may have been protected from RSV and other respiratory pathogens during their pregnancy. Molecular Diagnostics at the University Medical Center Groningen, The Netherlands.
Koopmans said a study her team conducted looking for antibodies in the blood of young children showed the effect of what she calls an “infection honeymoon.”
You really see that children in the second year of the epidemic have much lower antibodies to a group of common respiratory viruses. “They are becoming less vulnerable,” she said.
These factors may help explain the recent rash of unusual cases of hepatitis in young children. Scientists investigating the cases believe they may be caused, at least in part, by type 41 adenovirus, because it has been found in a large number of infected children. The possibility is puzzling, because the virus has not been seen to cause this type of disease in the past.
But some scientists believe this virus may have always been responsible for a portion of the small number of unexplained pediatric hepatitis cases that occur each year. Perhaps, as the thinking goes, there have been a lot of type 41 adenovirus infections over the past eight months due to increased susceptibility among children. This, in turn, can make something previously unseen visible.
“I sometimes think that to connect the rare complication points of common diseases, you just need enough cases to start putting the pieces together,” said Kevin Mesakar, MD, a pediatric infectious disease specialist at Children’s Hospital of Colorado. “And there is some suspicion that this could happen with cases of hepatitis.”
Read more: CDC expert answers questions about monkeypox
The epidemic-induced disruption of normal blending patterns means that even adults have not generated the levels of antibodies that would normally be obtained through regular exposure to bugs, creating larger pools of susceptible people.
Flu experts, for example, worry that when flu viruses come back in a serious way, the buildup of people who haven’t had a recent infection could translate into a very bad flu season.
Some studies suggest that after a period of a year or two where influenza transmission is low, there can be a significant decrease in the number of people who have influenza antibodies at levels high enough to be considered protective, Koopmans said. “It’s also possible that there will be a larger, more sensitive group in adults,” she said.
We are talking about endemic diseases that have a certain pattern of predictability. This pattern was partly seasonal but was also partly driven by the size of the immune or non-immune system. “The last part has increased, of course,” Koopmans said.
How will you play this? All eyes will be trained this fall at children’s hospitals to see if there is an increase in cases of polio called acute flaccid myelitis, or AFM, which is thought to be caused by infection with enterovirus D68.
Masacar, who is also an associate professor at the University of Colorado, has been studying AFM for the past eight years, since the first of a series of biennial case waves occurred in late summer and early fall 2014, 2016 and 2018.
Then in 2020, nothing. Same in 2021. Does that mean fall 2022 could see a spike in cases, because more children are at risk of getting D68 enterovirus? We must be prepared for that possibility, Mesakar said, stressing that he does not know what to expect.
“Now we have four years of children who haven’t seen this virus. We don’t know what’s going to happen. We don’t know when it will come back. But when it comes back, there are more vulnerable children out there who are not expected to have immunity.” “That’s what we’re seeing with a variety of different viruses.”
Thomas Clark, deputy director of the Division of Viral Diseases at the Centers for Disease Control and Prevention, said that public health workers fear the potential for outbreaks of immunization-preventable diseases due to the fact that many children around the world have missed out on childhood. Vaccinations during a pandemic.
But he said he now understands that this is not the only way the pandemic might affect infectious diseases.
“We are very focused on children who have not been adequately vaccinated with their routine childhood vaccinations because it is the setting for the introduction of measles. But then there were also a lot of children who did not have the usual kind of virus that they might have been exposed to.”
We may see differences in the severity of some diseases, Clark said, because young children who were protected from insects during the early stages of the epidemic may now contract them as they get older. Some diseases cause more serious symptoms if they are picked up as one gets older.
“Whether we’ll see this kind of thing in a short period of time I think is a big question mark,” Koopmans said. “But I think it’s definitely something worth watching closely.”
Some experts believe that the buildup of susceptible people is not the only way an epidemic might affect disease transmission patterns.
Read more: The “five pandemics” caused the death of a million Americans with the Corona virus
Lifting epidemic control measures could have helped the spread of monkeypox in the current outbreak in Europe, North America and beyond, said David Heymann, who chairs the panel of experts advising the WHO’s Health Emergencies Programme. Several cases of monkeypox have been diagnosed in men who have sex with men.
After two years of limited travel, social distancing and public gatherings, people are ditching the restrictions of the coronavirus control measures and embracing a return to life before the pandemic spread. Media reports indicated that the recent delirium in Spain and Belgium led to the transmission of the virus among some of the attendees.
Heyman, professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine, believes an outbreak of monkeypox may have been raging at low levels in the UK or elsewhere outside Africa for a long time, but may have already occurred. It only captures the public’s attention when international travel is back again.
“If you look at what has been happening in the world over the past few years, and if you look at what is happening now, you can easily wonder if this virus came into the UK two to three years ago, was moving from under the radar screen, [with] “The chains of transmission are slow,” said Heymann, who worked on smallpox eradication early in his career. “Then all of a sudden it all opened up and people started traveling and mixing.”
Prudden predicted that while all of this could take a precarious time over the next couple of years, things would eventually calm down.
“I think once you’ve infected a number of people, herd immunity kicks in and the virus goes away,” he said, referring to viruses in general. “We haven’t fundamentally changed the rules for infectious diseases.”
This article is reproduced with permission from STAT. First published May 25, 2022. Find the original story here.