When the coronavirus first crept into Dani Dumitriu’s pediatric ward, the pediatrician, like many colleagues, initially paid close attention to the consequences and side effects of the infection. After all, some viruses, such as Zika, are known to harm newborns. Most babies in the hospital put up with Covid-19 quite well, Dumitriu noted with relief, as did other physicians.
Soon after, however, an elusive but worrisome trend began to emerge. Dumitriu and her team at Presbyterian Morgan Stanley Children’s Hospital in New York City had been analyzing data they collected over two years: since late 2017, the team has been monitoring the development, communication behaviors and motor skills of infants up to six months old.
This article is included in Spektrum – Die Woche, 04/2022
It might be worth comparing the results of children born before and during the pandemic, Dumitriu thought. So she asked her colleague Morgan Firestein of Columbia University to look for any differences in neurological development between the two groups.
After a few days later, Firestein called back rather startled. "She said, ‘We’re in a crisis.’! No idea what to do: The pandemic is having an impact, and a significant one at that!’," Dumitriu recalls. She pulled some all-nighters and analyzed the data. In fact, infants born during the pandemic performed worse on average on tests of gross and fine motor skills and communication skills than peers born before the pandemic. In both groups, parents had collected data using a predetermined questionnaire.
It didn’t matter to the outcome whether the children’s parents were themselves infected with the virus or not: it wasn’t the infection that seemed to be the trigger, but some pandemic-related change in the environment. Dumitriu was floored: "We thought," she recalls, "my God, we’re talking about hundreds of millions of babies here!"
In general, many children acutely infected with Sars-CoV-2 are doing quite well. But initial research suggests that pandemic-related stress during pregnancy may be negatively affecting babies’ brain development in the womb. It could also be that stressed parents and caregivers interact differently or less with their young children, perhaps affecting physical and mental abilities. As is often the case, social and economic inequalities are likely to be a clear factor in determining how badly individuals are affected by the health side effects of the pandemic.
Lockdowns may also have had an impact: While they were instrumental in controlling the spread of the coronavirus, they also forced young families into greater isolation, which may have resulted in less time for playing with friends and siblings and less social contact. Many stressed and overwhelmed caregivers may not have been able to devote as much attention to babies and toddlers as they needed to.
Giving time that matters
How all this affects child development, parent-child relationships and peer relationships – that’s what "everyone was just trying to figure out," says developmental psychologist James Griffin: "Everyone was worried about it. A few teams have published initial study results; further studies are underway, but clear answers are hard to find.
This is due in no small part to the fact that many developmental psychology research institutions closed down during the pandemic. Not so Brown University’s Advanced Baby Imaging Lab: it stayed open during the Covid 19 pandemic – with a little less visitor traffic and a little more ramped-up hygiene rules. Medical biophysicist Sean Deoni and his colleagues there are using magnetic resonance imaging (MRI) and other techniques to study how environmental factors affect brain development in infants. They do this by testing babies’ motor, visual and language skills in the lab; part of a seven-year study by the U.S. National Institutes of Health on early childhood development and its impact on later health.
As the pandemic progressed, Deoni gradually heard more worrisome comments from his colleagues. "Our collaborators told me anecdotally, ‘Man, these kids take a lot longer to test,’" Deoni recalls. Noticing, he asked his team to systematically compare the average neurodevelopmental scores of children from year to year and look for variations.
It turned out that results during the pandemic were significantly worse than in previous years. "The results started to plummet at the end of last year and the beginning of this year," he said at the end of 2021. Comparing all participants, the pandemic babies scored nearly two standard deviations worse than those born before Corona times on a series of IQ test-like measures. Children from low-income families had the greatest losses, boys were more affected than girls, and overall gross motor skills were most impaired.
At first, Deoni assumed that the results were biased because of a very specific group of children being tested: Perhaps, during the pandemic, families whose children already had or were at risk of having developmental problems were the ones who applied for the test? Deoni ruled that out over time: The children who came in for testing did not differ in origin, birth events, or socioeconomic status from participants in earlier years. Their deficits, according to a worrisome trend in the evaluation, also increasingly accumulated with the duration of the pandemic. "The scale is huge. Just scary," says Deoni.
Will it stay?
The impact seems drastic. But at least they could be temporary. Moreover, predictions about long-term problems could not be drawn from this, other researchers caution. It’s really hard to say what this means for the future of babies, says developmental psychologist Marion van den Heuvel of Tilburg University in the Netherlands, for example. Because: "The IQ of infants does not predict much."This has been shown, for example, in a study of the development of girls who initially lived in orphanages in Romania and were then adopted by foster families before the age of 2.5. At age 4.5, they were less likely to have psychiatric problems than girls placed in homes. This situation is different from a pandemic, but observation suggests that hardships experienced by babies may even out later, once the problematic triggers are gone.
Deoni is currently revising his findings for publication in "JAMA Pediatrics". Initially, he had published the work on a preprint server, prompting a flood of concerned media reports and reactions from the research community. There was "real concern that these findings were published without proper peer review," says Griffin, who heads the Developmental Psychology Division at the National Institute of Child Health and Human Development in Bethesda.
But assuming the results eventually turn out to be valid: Why at all should babies born during the pandemic show cognitive and especially motor deficits?
Deoni suspects the problems may be due to a lack of interpersonal interactions. He and his team are checking this out in follow-up studies, not yet published, that documented interactions between parents and children at home. As it turns out, the number of words exchanged between father, mother and children decreased in the last two years compared to the period before that. Perhaps, Deoni speculates, infants and toddlers get fewer opportunities than usual to practice their gross motor skills because they don’t regularly romp with other children or go to playgrounds. That would be an unfortunate development, because the skills trained in the process otherwise "form a foundation for all others," says Deoni.
The risk of slowed development due to a lack of peer interactions seems real, as other research suggests. For a study published in early 2022, researchers in the United Kingdom asked 189 parents of children aged eight months to three years whether their children attended daycare or preschool during the pandemic, then tested the children’s language and executive skills. They did better when they were cared for in a group setting during the pandemic.
This had an even greater impact on children from low-income backgrounds. At risk, in addition to these children, appear to be those with non-white skin color. Fittingly, more and more research suggests that distance learning among school-age children further exacerbates already existing learning and developmental differences; such as those between children from affluent and low-income backgrounds or of different skin color.
In the Netherlands, researchers found that children in 2020 performed worse on nationwide tests of learning progress than they had in the previous three years. For children from families that are hard to reach by the formal education system, the effect was 60 percent stronger in some cases.
In several sub-Saharan African countries – such as Ethiopia, Kenya, Liberia, Tanzania and Uganda – some children may have lost up to an entire school year’s worth of learning, research shows. For the U.S., a study by the consulting firm McKinsey after the first lockdown found that students with non-white skin color were three to five months behind when school started in the fall – and still about one to three months more than their classmates with white skin color who were also behind.
Is wearing masks harmful in school and everyday life??
A number of studies have examined whether emotional development has been altered by the ubiquitous face masks. Children regularly faced mouth-to-nose protection in schools or other group settings due to the pandemic. The masks obscure parts of the face that are important for expressing and visually conveying emotions and language – and so it was important to clarify whether it affects children’s emotional and language development when these signals are omitted under the mask.
Psychologist Edward Tronick of the University of Massachusetts in Boston has been bombarded by e-mails from parents and pediatricians asking this question. Tronick is famous for his "Still Face" experiment: he used it in 1975 to show infants’ reactions to parents who suddenly interacted with the babies only with a frozen, rigid facial expression. Typically, infants then first try harder to get attention – but then, failing to do so, they gradually withdraw more and more into themselves and reacted with increasing upset and suspicion.
In Pandemic, Tronick and his colleague Nancy Snidman investigated whether masks have a similar effect: In experiments, the psychologists evaluated smartphone videos showing parents interacting with their babies before, during and after they put on the facial masks. Although the babies noticed when their parents put on the masks-they briefly changed their facial expressions, looked away or pointed at the mask-they then continued to interact with their parents as before. The mask blocks only one channel of communication, Tronick says: "The parent wearing a mask continues to communicate, ‘I’m interacting with you, I’m still here for you, I’m still connected to you’." Tronick and Snidman’s study has not yet received final peer review.
The perception of language or emotional messages also does not seem to be too impaired by face masks. A study published in May 2020 reports that two-year-olds understand words well spoken by adults wearing opaque face masks. Children "compensate for information deficits more easily than we think," says the study’s lead author, psychologist Leher Singh of the National University of Singapore. U.S. researchers determined that children of school age were less able to categorize the emotions of adults through facial masks: That becomes then about as difficult as with adults with sunglasses. In essence, however, the children nevertheless reached largely accurate conclusions. "There are many other cues that children can use to detect other people’s feelings – such as voice, posture, context," says study author Ashley Ruba of the University of Wisconsin-Madison.
Pregnancy and the stress of the pandemic
The pandemic could also affect children’s prenatal development. Looking for clues in this direction, several teams, including psychologist Catherine Lebel, of the University of Calgary in Canada. With her colleagues, she surveyed more than 8000 pregnant women during the pandemic. Nearly half reported suffering from anxiety symptoms, and one-third showed symptoms of depression – a significantly higher percentage than in the years leading up to the pandemic. How did this stress affect babies in the womb?
To find out, the researchers studied the brains of 75 babies three months after birth using magnetic resonance imaging techniques. In their preliminary publication, posted online in October 2021, they document a difference: if mothers reported greater prenatal stress, such as more frequent symptoms of anxiety or depression, their children were also more likely to experience certain differences in structural connections in the brain – those between the amygdala, a brain region involved in emotional processing, and the prefrontal cortex, an area that processes executive skills.
Lebel and her team had previously noticed a link between prenatal depression and the same differences in brain connectivity in a smaller study. They suggested that these brain changes in boys correlate with aggressive and hyperactive behavior in preschoolers. Other researchers have studied connectivity changes in adults: There appears to be a risk factor for depression and anxiety there.
Later development of children born in the pandemic may also be affected by prenatal stress. Research such as a study by psychologist Livio Provenzi of the IRCCS Mondino Foundation in Pavia, Italy, suggests as much. His team observed 12-week-old babies of mothers who had provided information about their stress and anxiety levels during pregnancy. The evaluation showed that babies with more stressed and frightened parents were less able to regulate emotions and attention at three months of age – for example, they lost interest in social stimuli more quickly and were more difficult to calm down.
Moriah Thomason of New York University Grossman School of Medicine is also investigating the effects of maternal stress on children’s brains and behavior in a separate study. It was still ongoing in early 2022. One point the child and adolescent psychologist highlights is that while there are all sorts of concerns about the possible effects of prenatal stress on babies born in the pandemic – it is by no means possible to infer from the first early studies that babies will have problems for the rest of their lives. "Children are very adaptable and flexible. Things will get better, and we expect that children will be able to cope well with a lot of what happens," Thomason says. She doesn’t expect to have to say at some point that the pandemic has created an entire generation of damaged children.
Research on the aftermath of past disasters seems to bear this out: stress in the womb can be harmful to babies, according to the study, but it doesn’t have to have long-term effects. This is confirmed by a study on the consequences of severe flooding in Queensland, Australia, in 2011: children of mothers who had been significantly stressed in the wake of the catastrophe showed deficits in problem-solving and social skills at the age of six months when compared with peers of mothers who had been less affected. But this changed over time: at the age of 30 months, this effect was no longer discernible. Infants also did better the more parents were attentive to the babies’ needs.
What to do, where is caution advised?
As of early 2022, research on the pandemic’s impact on babies provides a mixed, still preliminary picture: many scientists say it’s just too early to make reliable, meaningful interpretations. It may turn out that the initial indications from early and unpublished studies are not confirmed in the end, says medical psychologist Catherine Monk, a colleague of Dimitriu at New York-Presbyterian. This could have various causes. It is conceivable, for example, that those parents who chose to participate in initial studies did not form a representative sample. For example, they may have already noticed behavioral changes in the children and therefore been particularly concerned. It may also have had a perhaps small but disruptive impact that in pandemic times people had to wear face masks for the psychological tests that required a personal appearance, Monk says.
In addition, initial, rapidly conducted studies on the topic may be subject to the incentive to publish particularly interesting results above all else. Thomason pointed this out as early as 2021 in an opinion piece in the journal JAMA Pediatrics. Scientists are "quick to jump on the bandwagon when it comes to uncovering changes that are harmful to health. This kind of thing gets media attention, and it gets published in high-profile journals," she says.
A clearer picture is likely to be painted by large-scale studies and collaborations already being initiated by various researchers and funders. The U.S. National Institute on Drug Abuse is funding studies as part of the Healthy Brain and Child Development Study, which is investigating how maternal stress and drug use during the pandemic affect child development. Newly formed networks and conferences should bring researchers together and encourage the sharing of new data. In March 2020, Thomason had already launched the international COVID Generation Research Alliance: Addressing scientists who study families with young children during the pandemic. The alliance, which hosted a research summit in November 2021, includes researchers from 14 countries ranging from North and South America to Europe, Australia, Asia, the Middle East and Africa.
Helping them grow and shake it off
Even in the event, the pandemic really does change children: Six-month-olds’ brains are malleable, Dumitriu says, you can nurture their development, and there’s plenty of time in any case to repair potential damage and circumnavigate a public health crisis scenario. Parents can also help by regularly playing and talking with their infants and giving them opportunities to interact with others in a safe environment. Promoting programs that support families and children can also make a difference. Lebel’s study shows that the prenatal stress of expectant mothers drops significantly when they experience social support from close caregivers during pregnancy. There’s a lot of potential here anyway, in and around the prenatal care ecosystem, says Monk.
In the end, the research solidified the assumption that most children will probably be able to cope with the side effects of the pandemic – although they will probably struggle more than they have in the past. In difficult cases, we should take countermeasures as soon as possible, warns Deoni: "Children are undoubtedly very resilient, but we also know how important the first 1000 days in a child’s life are. This is where the critical fundamentals are forming."At the beginning of 2022 the first pandemic babies born in March 2020 are already more than 650 days old. These children are a product of their environment, says Deoni: In the end, it will be the input we give them, how we play with them, read to them and love them that will make the difference.