COVID-19: Weekly Update (October 3, 2022)

A study suggests that COVID-19 vaccination slightly prolongs the menstrual cycle. Other research indicates that people, especially young adults, became less extroverted and open during the pandemic.

As of September 28, the 7-day moving average of daily new cases decreased by 13.1% compared with the previous week. However, the percentage of positive COVID-19 tests slightly increased, according to the Centers for Disease Control and Prevention (CDC).

There was also a 7.4% decline in new hospitalizations and a 6.7% drop in new deaths compared to the previous 7-day moving average.

Most counties (73.7%) are with low COVID-19 community level. In addition, nearly one in four (22.9%) counties are with a medium community level, and 3.3% have high community level.

Changes in the menstrual cycle

A study funded by the National Institutes of Health (NIH) confirms earlier findings that COVID-19 vaccination is linked to an increase in menstrual cycle length of less than one day.

Researchers analyzed de-identified data from the fertility tracking app Natural Cycles. The study included 19,622 individuals aged 18-45 years globally. Of these, 14,936 were vaccinated, and 4,686 were not.

Most individuals had mRNA vaccines, with two-thirds (66.48%) receiving Pfizer-BioNTech and 17.46% receiving Moderna. Over 9% of individuals received Oxford-AstraZeneca vaccines, and 1.89% of individuals had Johnson & Johnson, both of which are vaccines which use an adenovirus vector to deliver the mRNA which encodes the information for the cell to make the spike protein. Other people received vaccines such as Covaxin, Sinopharm, Sputnik, and Sinova.

The researchers analyzed data on at least three consecutive cycles before vaccination and at least one cycle after. On average, vaccinated people experienced an increase of 0.71 days after the first dose and a 0.56 days increase after the second dose in each cycle they were vaccinated compared to unvaccinated people.

People who received two doses within the same cycle had a 3.7 day increase in cycle length, were more likely to experience a >8 day change in cycle length (13.5% vs 5%) and had not returned to baseline the next month (0.85 day increase). Those who received one dose per cycle returned to baseline the next cycle.

The increase, however, was not associated with any change in the number of days of menses (days of bleeding). In addition, changes in cycle length did not differ according to the type of vaccine received.

Research is needed to understand what mechanism is causing this change in cycle length and what the implications are – if any – for fertility. This study offers an important contribution to the literature regarding the effects on menses from a large international cohort with prospective data collection (reducing the effect of recall bias) and includes people who are not using hormonal contraception (to understand the effect of the vaccine on menses without the influence of exogenous hormones).

The pandemic changed personalities

A recent study published in the PLOS ONE journal examined personality changes relatively earlier (2020) and later (2021–2022) in the pandemic compared to pre-pandemic levels. Researchers used longitudinal assessments of the personality of 7,109 people aged from 18 through 109 years from the Understanding America Study.

According to the previous findings, neuroticism declined very slightly in 2020 compared to pre-pandemic levels, but there were no changes in extraversion, openness, agreeableness, and conscientiousness.

However, later in the pandemic, in 2021–2022, there was no significant change in neuroticism compared to pre-pandemic levels, but extraversion, openness, agreeableness, and conscientiousness slightly declined, especially in young adults under 30.

“The changes were about one-tenth of a standard deviation, which is equivalent to about one decade of normative personality change,” researchers say.

The researchers note that the effect of age cannot be disentangled from the cohort effects of the pandemic, but they observed that “younger adults showed disrupted maturity in that they increased in neuroticism and declined in agreeableness and conscientiousness.”

Personality changes were different in Hispanic/Latino people. In 2020, participants of this ethnic group did not decrease in neuroticism but saw a decline in agreeableness earlier than non-Hispanic/Latino participants. Researchers say this could be due to the more severe impact of the pandemic on this group.

Long COVID-19 in children

The American Academy of Physical Medicine and Rehabilitation (AAPMR) released guidance on diagnosing and treating pediatric patients with long COVID-19.

Researchers note that the condition's management, rehabilitation, and symptoms differ in children and adults. The most common symptoms in pediatric patients are fatigue and attention problems, ongoing fever, headaches, sleep issues, and new mental health issues.

According to the guidance, rehabilitation for children with long COVID-19 "should be individually tailored and move at the patient's own pace rather than a set timetable."

While many patients with autonomic dysfunction symptoms appear to tolerate physical activity while engaged in the activity, the symptoms may occur after several hours or even days.


CDC. Covid Data Tracker Weekly Review.

British Medical Journal. Association between menstrual cycle length and covid-19 vaccination: global, retrospective cohort study of prospectively collected data.

NIH. Study confirms link between COVID-19 vaccination and temporary increase in menstrual cycle length.

PLOS ONE. Differential personality change earlier and later in the coronavirus pandemic in a longitudinal sample of adults in the United States.

AAPMR. AAPM&R Long COVID Pediatrics and Autonomic Dysfunction Guidance Statements Released.

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