The Economist February 6th 2021 Science & technology 65protein called ace2. The variant first found
in South Africa, known as b.1.351, has fewer
mutations than b.1.1.7, but three of them
appear to enhance resistance to antibodies
that people develop in response to the
wild-type virus.
This enhanced resistance has caused
concern that the variants in question
might be able to evade immunity people
had gained from previous infections or
vaccination—particularly since all vac-
cines currently in use are intended to pro-
voke an immune response to spike. Ac-
cording to America’s Centres for Disease
Control and Prevention, variants will need
to accumulate multiple mutations in spike
to evade vaccine-induced immunity. Nev-
ertheless, the results of trials announced
on January 28th showed that a jab made by
Novavax, an American pharmaceutical
firm, which was almost 90% effective in
preventing symptoms of covid-19 in Bri-
tain, was only 50-60% effective in South
Africa. Johnson & Johnson, another Amer-
ican firm, found a similar result when it
tested its single-dose vaccine in South
Africa, the United States and parts of Latin
America. Its vaccine, too, was less effective
in South Africa than in the other places.
That suggests b.1.351 is less amenable to ex-
isting vaccines than is its predecessor.
Even so, the vaccines worked well enough
to prevent serious disease in most cases.
Vaccine-makers will have to continue
adapting their vaccines to keep up with
mutations in coming years. This may be
done by providing booster shots tailored to
different variants, or by creating bivalent
vaccines that work against both the origi-
nal strain and a mutant. Moderna, the
maker of a vaccine that has already been
approved for use in several places, is plan-
ning to work on a booster that will enhance
the body’s immune response to b.1.351 and
could work in combination with all of the
other leading vaccine candidates. Clinical
trials of this approach are scheduled to
start in July, and should be completed
within a year. Pfizer and BioNTech, the
partners who created another widely ap-
proved vaccine, say they can produce a jab
adapted to new variants in six weeks.
America’s Food and Drug Administration,
that country’s medical regulator, has
promised a “streamlined” process for au-
thorising updated vaccines. This would be
satisfied by small trials intended to make
sure a modified vaccine triggers a suitable
immune response, rather than the big, so-
called phase-three trials required to test a
completely new product.
Researchers, then, are still learning
about how the new variants behave. But ul-
timately the best way to stop a virus from
evolving is to prevent it from spreading by
whatever means are available. All the more
reason, therefore, to vaccinate as quickly
and as widely as possible.
Daughters and divorceTeenage rampage
D
aughters havelong been linked with
divorce. Several studies conducted in
America since the 1980s provide strong evi-
dence that a couple’s first-born being a girl
increases the likelihood of their subse-
quently splitting up. At the time, the re-
searchers involved speculated that this
was an expression of “son preference”, a
phenomenon which, in its most extreme
form, manifests itself as the selective abor-
tion or infanticide of female offspring.
Work published in the Economic Jour-
nal, however, debunks that particular idea.
In “Daughters and Divorce”, Jan Kabatek of
the University of Melbourne and David Ri-
bar of Georgia State University, in Atlanta,
confirm that having a female first-born
does indeed increase the risk of that child’s
parents divorcing, in both America and the
Netherlands. But, unlike previous work,
their study also looked at the effect of the
girl’s age. It found that“daughter-divorce”
risk emerges only ina first-borngirl’steen-
age years (see chart).Beforetheyreachthe
age of 12, daughtersarenomorelinkedto
couples splitting upthansonsare.“Iffa-
thers were really morelikelytotakeoffbe-
cause they preferred sons, surely they
wouldn’t wait 13 yearstodoso,”reasonsDr
Kabatek. Instead, heargues,thefactthat
the risk is so age-specificrequiresa differ-
ent explanation, namelythatparentsquar-
rel more over the upbringingofteenage
daughters than of teenagesons.
Taken over the years,thedaughteref-
fect, though real, issmall.IntheNether-
lands, by the time theirfirst-born is18,
20.12% of couples willhavedivorcedif that
child is a son, comparedwith20.48%if sheis a daughter—an increase in probability of
1.8%. But in the five years when the first-
born is between the ages of 13 and 18, that
increase goes up to 5%. And it peaks, at 9%,
when the child is 15. In America, for which
the data the researchers collected were
sparser than those in the Netherlands, the
numbers are roughly double this.
Anyone who has—or has been—a teen-
ager knows how turbulent those years can
be. Surveys confirm that teenage daughters
and fathers, in particular, get on each oth-
er’s nerves. They also show that parents of
teenage daughters argue more about par-
enting than do the parents of sons, and
that mothers of teenage daughters report
significantly more disagreements with
their partners over money, and become
more open to the idea of divorce. Earlier re-
search has also shown that one of the most
common things parents fight over is how
much they should control their teenagers’
personal choices, such as how they dress,
whom they date and where they work.
In light of all this, it is intriguing to note
that Dr Kabatek and Dr Ribar found one
type of couple who seem immune to the
daughter effect: those in which the father
grew up with a sister. Having seen things
somewhat from a sister’s point of view may
act as a sort of social inoculation. Daughters provoke parental strife,
but only when they are teenagersPeak pique
Excess risk of divorce forcoupleswithfirst-born
daughters compared withfirst-bornsons*,%Source:“Daughtersanddivorce”,byJ. Kabatek
andD.C.Ribar,theEconomicJournal, 2020 *Ofthesameage151050-5-10
2520151050
Age of child↑ Higher risk
with daughters↓ Lower risk
with daughters 95% confidenceMarine ecologyPlastic oases
T
he oceandeep, where pressure is high,
light absent and nutrients scarce, is of-
ten seen as a desert. But, as with other de-
serts, it has oases. Hydrothermal vents,
methane-gas seeps and whale corpses are
hot spots for marine wildlife. And observa-
tions reported in Environmental Science and
Technology Lettersby Song Xikun of Xia-
men University, in Fujian, and Peng Xiao-
tong of the Chinese Academy of Sciences’
campus at Sanya, in Hainan, suggest these
natural loci of biodiversity are now being
joined by unnatural ones made of plastic.
Carried down slopes by submarine
landslips, plastic objects accumulate in
patches in the deep. Dr Song and Dr Peng
had seen pictures showing sponges, corals
and anemones on or near these accumula-
tions. This led them to wonder about their
ecology. So they went to have a look.
Their vehicle was Shen Hai Yong Shi, a
deep-diving submarine that carries a six-
person crew. This descended nine times
into the Xisha trough, a feature at the bot-
tom of the South China Sea, in search ofPollution is boosting the amount of
animal life in the depths