‘Virus Pandemonium’: How Covid Pandemonium Changed Known Virus Patterns

Respiratory viruses, particularly those affecting children, tend to be seasonal: they occur more often at certain times of the year, and doctors know when to be on the lookout for waves of illnesses such as influenza, RSV (respiratory syncytial virus), or adenovirus.

But what pediatricians in Brazil and abroad have seen recently is completely at odds with this predictability.

And behind this atypical picture seem to be the side effects of the Covid-19 pandemic – both the isolation it has imposed on societies and the “immune blackout” that this has caused, as well as the direct action of Sars-CoV-2.

“Since the pandemic hit us, in March 2020, we have seen a drastic change in the pattern” of the most common viruses, infectologist Francisco Oliveira Júnior, medical manager at Sabará children’s hospital in São Paulo, tells BBC News Brazil.

The change began right at the beginning of the pandemic. With social isolation, the use of masks and the closing of schools and common spaces, children and adults stopped having contact with various pathogens.

“The case of the flu was very remarkable: it simply disappeared in 2020. We researchers never imagined that this would happen”, explains to the report Ellen Foxman, assistant professor at the Yale School of Medicine, in the United States, and researcher of virus behavior. .

In addition to influenza (which causes the flu), the RSV (which causes bronchiolitis in young children) and rhinovirus (which causes the common cold) also practically disappeared throughout 2020, recalls Francisco Oliveira.

Then, in 2021, these viruses started to reappear — but out of season.

“To our surprise, RSV and influenza appeared in the summer even in adults,” says the doctor.

In the current cold months, when viruses actually proliferate more quickly, a greater than usual amount of virus is causing visits and admissions to children’s hospitals. Starting with Sars-CoV-2.

At the Pequeno Príncipe pediatric hospital in Curitiba, from May to June, the number of hospitalizations for covid-19 increased by 30%, and most cases were of unvaccinated children (or only with the first dose) and under 5 years old ( who have not yet received the vaccine).

On the day he spoke to the report, on June 17, Victor Horácio, a pediatric infectious disease specialist at Pequeno Príncipe, said that a wing of 12 children’s beds was fully occupied by patients with covid-19.

Apart from that, reports Horácio, there have been “many more cases of RSV, adenovirus and parainfluenza (which also cause respiratory diseases). The clinical picture may not only be stronger, but more frequent”.

And although the most serious cases of RSV continue to occur in babies, even teenagers have suffered more from the disease, according to the doctor at Pequeno Príncipe Hospital.

In Sabará, hospitalizations for adenovirus, parainfluenza and rhinovirus have increased in recent weeks. “Before, the prevalence of these viruses was lower”, explains Oliveira.

“It’s an anomalous situation”, says the pediatrician from Rio de Janeiro, Daniel Becker, who classifies the current situation as a “pandemonium of viruses”.

“We have seen an excessively large number of children catching consecutive diseases, one after the other. It is a personal observation, but there is a consensus among doctors that the order of magnitude of contamination is well above normal”, he evaluates.

But what explains the changes in seasonality and clinical status of viruses so well known in medicine?

‘Immunity deficit’

It is something that is still being investigated, but, according to five doctors consulted by the report, a key point is that there seems to be an “immunity deficit” caused by the period of social isolation – in all age groups, but particularly in children.

The fact that they didn’t catch so many viruses in the months of the pandemic was a relief amid the tragedy and disruptions of Covid-19. But that left their immune systems untrained to face common pathologies and created population groups more vulnerable to some viruses and bacteria, says a French study co-authored by doctor François Angoulvant, who since 2020 has followed the evolution of infectious diseases in Paris.

In addition, it is possible that Sars-CoV is interfering with the outcome of some infections. An emblematic case of this concerns the outbreaks of the mysterious childhood hepatitis seen in recent months.

One possibility studied by doctors is if children who were infected with Covid-19 and then caught the so-called adenovirus 41 — which causes stomach problems — ended up having an unexpected response from the body that may have led to hepatitis, explains Oliveira Júnior.

Are viruses changing?

Overall, another hypothesis being investigated is whether common viruses have changed in the last two years.

A study by the University of Sydney, Australia, published in the journal Nature Communications, assesses that the pandemic “hugely changed the incidence and genetics” of RSV in the country, which has had one of the strictest lockdowns on the planet.

As in the rest of the world, the VSR had its seasonality messed up in Australia: it disappeared from the map in 2020, but was one of the first to reappear — but in summer rather than winter — when the country reopened.

The Australian researchers decided to genetically sequence the main out-of-season outbreaks of the virus. “A surprising finding was a major ‘collapse’ of RSV strains already known before Covid-19 and the emergence of new strains, which dominated outbreaks” in large parts of the country, reads a statement from the University of Sydney.

“We need to reassess our current understanding and expectations of common viruses, including influenza, and our approach to managing them,” said John-Sebastian Eden, the study’s principal investigator. “We need to be vigilant: some viruses may have all but disappeared, but they will possibly return in the near future, at unusual times and with a greater impact.”

Ellen Foxman of Yale and François Angoulvant, a doctor in Paris, however, don’t think the viruses themselves are changing — the main change is in our relationship with them.

“We are the ones who change (our behavior in the pandemic), not the viruses”, says Angoulvant to BBC News Brasil. “We’ve also seen that we don’t fully understand the seasonality of viruses and that we can’t extrapolate the behavior of one virus to the others — our immune system’s history doesn’t respond the same to all viruses.”

“The pandemic served to show us that things we thought were the fault of the weather (in the case of autumn/winter viruses, for example) are not necessarily so”, adds Ellen Foxman. “Our behavior plays a much bigger role than we thought.”

In addition, there is still much to be deciphered about our immune system. For example, a great fear during the Covid-19 pandemic was that an influenza epidemic would coincide with that of Covid-19, leading to a potential further collapse of healthcare systems.

But, although there have been cases of co-infection of influenza and Sars-CoV-2, the “twin epidemic” did not happen.

The reason for this is being studied by Foxman’s lab at Yale.

“We researched whether, when a virus advances with great prevalence (as in the case of Sars-CoV-2 with its hyper-transmissible variants), it ends up causing people who have recently been infected to have their immune system on high alert, which can ward off other viruses,” Foxman tells BBC News Brazil.

“It’s what we call viral interference, but that’s not fully understood yet.”

In any case, even if viral interference ends up being proven, it is probably not something permanent, says Francisco Oliveira Júnior, from Sabará. And viruses, with their cycles of ups and downs, are “disputing space” in an attempt to proliferate in our bodies.

“We don’t know what niche Sars-CoV-2 will occupy, as more people get vaccinated or have immunity. It is capable of many mutations, which can cause infections, not necessarily more serious – but it is an unpredictable virus and can arise a strain of greater severity that may affect subgroups with a worse immune response.”

Ellen Foxman suspects that, over time, Covid-19 will eventually become a seasonal winter virus (just as other coronaviruses tend to be). And that, as the behavior of societies becomes more similar to pre-pandemic periods, the typical seasonality of other viruses also returns to its known patterns.

What can parents do against childhood viruses?

In the meantime, pediatrician Daniel Becker gives tips on how to deal with frequent viral cases in children.

“It is important to avoid going to the emergency room on the first day of fever, except in the case of small babies (when any fever has to be evaluated by a doctor). This is because, due to the context of the emergency room, many sometimes children end up being medicated unnecessarily, even with antibiotics, and spend hours in the service queue, exposed to a co-infection”, he says.

“If the child is in a good general condition, he can be observed carefully and treated with plenty of fluids, honey, nasal wash, hot bath and steam. And if he is down because of fever, an antipyretic can relieve the discomfort. “

If the condition worsens or persists, then it may be time to seek medical attention.

And, for children who have a lot of phlegm, but without fever and in a good mood, playing outdoors helps to improve immunity and strengthen the cardiorespiratory system, adds Becker.

Finally, “we know that kids are eating more ultra-processed foods, and that’s not good, because it worsens the microbiome profile.” It refers to the set of microorganisms that live in parts of our body, such as the intestinal system, and that have been shown to play an important role in general health, including immunity.

So a diet rich in fruits, vegetables, grains and legumes will help not only the general health of the body, but also its power to fight infections.

In the long run, what can we learn from this?

In addition, all the experts consulted by BBC News Brasil say that the viral mess caused by the pandemic brings important lessons, both for individuals and for public policies.

The first lesson has to do with vaccines: keeping the vaccination schedule up to date, including (but not limited to) against Covid-19, is essential to protect children and adults from the pathogens for which there are immunizations.

Governments and vaccine manufacturers may have to adapt to offer vaccines (such as the flu) for longer, beyond typical seasonalities, at least for now. And research for new vaccines, such as one against RSV, or stronger ones, as in the case of Covid-19, will continue to be important.

To prevent viral cases in children, protective measures remain essential, including using alcohol gel, keeping your hands always clean and controlling going to agglomerations – including adults, who are often great virus transmitters for children.

“Another thing I never imagined is how the masks turned out to be so effective,” says Ellen Foxman.

Even before the pandemic, she says, “we could have prevented the spread of so many diseases if we didn’t go to work sick, or let everyone go without a mask in pediatric offices, passing viruses on. Wearing a mask or working from home can reduce the burden of these diseases so much. diseases. I hope we remember these lessons when the pandemic passes.”

‘This text was originally published in https://www.bbc.com/portuguese/geral-61902861′