The following is a summary of some recent studies on Covid-19. They include research that warrants further study to corroborate the findings and that has yet to be certified by peer review.

No link seen between vaccines and menstrual changes

Many women have reported noticing changes in their menstrual cycle after being vaccinated against Covid-19 but a new study of 1,273 women in the UK found no correlation, according to a report posted on Monday on medRxiv ahead of peer review. The women in the study kept careful records of their cycles and their vaccination dates.

"We were unable to detect strong signals to support the idea" that Covid-19 vaccines are linked to changes in timing or flow of women's periods, said Victoria Male from Imperial College London. It is possible that larger studies, or studies in other countries, might find links, she said.

"It is important to note that most people who report such a change following vaccination find that their period returns to normal the following cycle." Other studies have found no evidence that the vaccines affect female fertility, Male added.

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Safe to get Covid-19 vaccine, flu shot together

It is safe to administer Covid-19 vaccines and flu vaccines to patients at the same time, and doing so might increase vaccination rates, according to a report published on Thursday in The Lancet. 

Researchers randomly assigned 697 adult volunteers to receive their second dose of either the mRNA vaccine from Pfizer/BioNTech or the viral-vector vaccine from AstraZeneca/Oxford, along with one of three influenza vaccines for the 2020-2021 season (FluAd or Flucelvax from Seqirus UK or Flublok from Sanofi) or a placebo.

Most reactions to the shots were mild or moderate, and antibody responses to the vaccines were not adversely affected by getting two shots at once, the study found. Giving both vaccines at a single appointment "should reduce the burden on health-care services for vaccine delivery, allowing for timely vaccine administration and protection from Covid-19 and influenza for those in need," the research team concluded.

Lung cancer patients respond well to Covid-19 vaccines

Lung cancer patients may get good protection from mRNA Covid-19 vaccines even while undergoing treatments that suppress the immune system, a small study suggests.

From January through July this year, researchers in France administered the vaccine from Pfizer/BioNTech to 306 lung cancer patients, 70 per cent of whom had recently received immunosuppressive therapies that impair the body's ability to respond to vaccines.

Patients with Covid-19 antibodies from a previous infection received only one dose; most patients, however, received both doses, according to a paper released on Monday and scheduled for publication in the Journal of Thoracic Oncology.  About 10 per cent of the patients failed to develop antibodies in response to the first two doses and received a third dose, which successfully induced antibodies in all but three individuals who also had blood disorders known to impair the effect of the vaccines.

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The researchers noted that before vaccines, the death rate among lung cancer patients who developed Covid-19 was 30 per cent. In this seven-month study, only eight patients, or 2.6 per cent of the total, developed mild cases of Covid-19. Because the study was small and not randomised, the investigators called for more research to confirm their findings.