COVID immunity, 3D nucleus the week in infographics

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unequal vaccine roll out

Low-income nations are too often the last to receive life-saving vaccines, as these charts show. Huge delays in the global distribution of COVID-19 vaccines mean that many fewer people have received a dose in poorer countries than in richer ones. Vaccines against Haemophilus influenzae and Streptococcus pneumoniae have also been much slower to reach low- and middle-income nations. Our feature reports on a major initiative to correct that imbalance by building vaccine-making capacity throughout Africa, South America, Asia and Eastern Europe.

Source: Our World in Data

After math infection

This chart shows that natural immunity induced by infection with SARS-CoV-2 lasts for months before fading away. A new study, which has not yet been peer-reviewed, analyzes infections in the entire population of Qatar between 28 February 2020 and 5 June 2022. The authors looked at how effectively people who were infected with a pre-Omicron variant one of those prevalent before the spread of Omicron were protected against reinfection with another pre-Omicron variant. Effectiveness peaked at 90.5% in the 7th month after the first infection and fell to about 70% at 16 months. The study also found that infection with any SARS-CoV-2 variant is highly effective at combating severe COVID-19 after reinfection and that this showed no signs of declining. But scientists warn that the study results do not mean that infected people can skip vaccination.

Source: Ref. 1

Location in the nucleus matters

A paper in Nature reported that the 3D location of chromosomes in the nucleus affects their likelihood of being incorrectly segregated during cell division an abnormality that often occurs in cancers. By studying human cells, the authors found that chromosomes found at the periphery of the nucleus in the interphase stage of the cell cycle are more likely to give rise to abnormalities than chromosomes located centrally.

As the cell begins to divide during the prometaphase stage, a structure called the mitotic spindle attaches to each chromosome. Later, during anaphase, the spindle pulls chromosomes into the two newly forming daughter cells. Peripheral chromosomes might take longer than central chromosomes to make proper contact with spindle components and to align in the middle of a dividing cell. This can result in peripheral chromosomes not being correctly included in the newly forming nucleus of a daughter cell. Defects might therefore arise, such as abnormal numbers of chromosomes and the formation of a chromosome-containing structure called a micronucleus.

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