Latest knowledge on Covid-19

Dr Adrian Hyzler Chief Medical Officer at Healix International

Dr Adrian Hyzler
Chief Medical Officer

Developments from 26th February 2021

Brazil’s coronavirus outbreak has killed 251,498 people, the health ministry reported on Thursday, as it recorded a further 1,541 fatalities in the last 24 hours, the second highest daily death toll since the pandemic hit the country a year ago. With 65,998 new cases of coronavirus reported on Thursday, Brazil has now registered 10,390,461 cases, in the world’s third worst outbreak outside the US and India and its second deadliest. The country is entering a new and more dangerous stage of the pandemic with at least two variants of the coronavirus that are three times more contagious than the ‘wildtype’ coronavirus in general circulation. The health service has already distributed over 14 million vaccine doses with ambitious plans to have inoculated half of the country’s 210 million residents by the middle of the year. Brazil is using mainly the Coronavac vaccine made by China’s Sinovac Biotech Ltd and, to a lesser extent, the AstraZeneca vaccine developed with the University of Oxford, but they are negotiating to secure doses of the Pfizer/Moderna and the yet to be approved Johnson & Johnson vaccines.

Johnson & Johnson’s single-dose coronavirus vaccine is about 66% effective at preventing moderate to severe forms of COVID-19.The vaccine had a 72% overall efficacy rate in the United States and 64% in South Africa, where a highly contagious variant is prevalent and is now driving most cases. The efficacy in South Africa was seven percentage points higher than earlier data released by the company. More importantly, the vaccine demonstrated 86% efficacy against severe forms of Covid-19 in the US, and 82% against severe disease in South Africa. The newly released trial data, which include the FDA’s first technical analysis of the company’s 45,000-person clinical trial, presented evidence that the vaccine was safe, with noticeably milder side effects than the Pfizer and Moderna vaccines and without any reports of severe allergic reactions like anaphylaxis. It is anticipated that the vaccine may receive Emergency Use Authorisation in the next few days. J&J tested its single-dose vaccine in 44,000 people in the US, Latin America and South Africa. Because different variants of the virus are circulating in different countries, researchers analysed the results geographically. Early indicators suggest that the vaccine has similar efficacy to the AstraZeneca/Oxford two-dose vaccine that is also a ‘vector-mediated’ vaccine, but not as strong performance as the mRNA vaccines from Pfizer and Moderna. However, the vaccine requires only a single jab and can be safely stored for at least three months at fridge temperatures. This will be a major boost to the US vaccine rollout, though supplies are expected to be severely limited until around June, by which time J&J are contracted to supply 100 million doses to the US.

New studies have revealed that the coronavirus variant first discovered in California in December is more contagious than the ‘wildtype’ virus that is in general circulation. The findings raise concerns that emerging mutants that lead to ‘variants of concern’ could blunt the sharp decline in new cases in the state and perhaps elsewhere. Researchers have been performing extensive genomic sequencing of the new variant, known as B.1.427/B.1.429, to pinpoint its origin and track its spread. It has shown up in 45 states to date as well as in several other countries, including Australia, Denmark, Mexico and Taiwan, but significant transmission has, up to now, only been seen in California. The coronavirus variant of concern first detected in Britain has been reported in 94 countries, an increase of eight. Local transmission of the variant, as opposed to imported cases, has been reported in at least 47 countries. The variant first noted in South Africa was recorded in 46 countries, up two, with local transmission in at least 12 of those nations. The P1 ‘Brazilian’ variant was detected in 21 countries, up six, with local transmission in at least two countries.

The latest trials into the Pfizer COVID-19 vaccine suggest that it is highly effective at preventing SARS-CoV-2 infections, whether they cause symptoms or not – this is the strongest evidence yet that vaccines could control viral transmission. A research group at Public Health England tracked the effectiveness of the vaccine made by Pfizer and BioNTech in 23,000 UK healthcare workers who were already part of a long-term study of SARS-CoV-2 immunity. Volunteers were tested regularly for SARS-CoV-2, regardless of their symptoms. The vaccine was 70% effective at preventing both symptomatic and asymptomatic infections in the period beginning three weeks after the first dose; this grew to 85% shortly after a second dose of the mRNA vaccine. This finding is the first evidence that Pfizer’s vaccine might block transmission. Moderna’s trial found some hints that vaccinated people were less likely to develop an infection without symptoms, while AstraZeneca found that its vaccine reduced asymptomatic infections by about half. Johnson & Johnson looked for asymptomatic infections by checking for coronavirus antibodies 71 days after volunteers got a vaccine or a placebo. The new analyses estimate that the vaccine has an efficacy rate of 74% against asymptomatic infections. But that calculation was based on a relatively small number of volunteers. These data all point to effectively reducing transmission through vaccination.

The amount of SARS-CoV-2 coronavirus in a person’s body, and particularly in the nasal passages, is a major factor in determining whether they are likely to transmit the virus to others, according to a study of nearly 300 infected people and their close contacts. Researchers monitored 282 people who had recently developed mild symptoms of COVID-19 and 753 of their close contacts. Infected people with a relatively high ‘viral load’, a measure of the amount of virus in the body, were much more likely to pass on the virus than were those with a low viral load. They were no more likely to transmit the virus if they had a cough than if they didn’t. PCR tests are able to determine not just whether or not someone has viral particles in the sample but also the amount of viral particles – this measurement is called the ‘cycle threshold’ (Ct value). The higher the Ct value the lower the viral load. The planned UK human challenge trials will attempt to determine the concentration of virus that is sufficient to cause infection.

What do we know about Covid-19?

Knowledge and advice relating to the disease is constantly evolving. To help support our clients, Healix’s Chief Medical Officer has produced a comprehensive reference guide, updated weekly, containing everything you need to know about COVID-19, as well as sharing our latest advice for travellers and employees.

What’s inside?

  • Overview
  • Transmission
  • Symptoms & Risk Groups
  • Treatment
  • Long Term Health Effects
  • Prevention
  • Vaccine Approval Chart
  • Testing
  • Latest Advice for Travellers
  • Country Bandings

To view our Coronavirus Pandemic Information Hub, click here.

Reference: Covid-19 country band categorisation


>250 cases per 100,000 over 7 days

  • Albania
  • Andorra
  • Bahrain
  • Czech Republic
  • Estonia
  • Latvia
  • Malta ↑
  • Mayotte
  • Monaco ↑
  • Montenegro
  • San Marino
  • Seychelles
  • Slovakia
  • Slovenia
  • St Lucia
  • St Vincent & Grenadines
  • Turks & Caicos
  • USA – New York, S Carolina


>50-250 cases per 100,000 over 7 days

  • Antigua and Barbuda
  • Argentina
  • Aruba
  • Austria
  • Barbados
  • Belarus
  • Belgium
  • Bosnia & Herzegovina
  • Botswana
  • Brazil
  • Bulgaria
  • Canada ↑
  • Chile
  • Colombia
  • Croatia
  • Cuba
  • Cyprus
  • Denmark ↑
  • Dominican Republic
  • Falkland Islands
  • France
  • Georgia
  • Germany
  • Gibraltar
  • Greece
  • Hungary
  • Iran
  • Iraq ↑
  • Ireland
  • Israel ↓
  • Italy
  • Jamaica
  • Jordan
  • Kosovo
  • Kuwait
  • Lebanon ↓
  • Lithuania
  • Luxembourg
  • Malaysia
  • Maldives
  • Malta
  • Moldova
  • Monaco
  • Namibia ↑
  • Netherlands
  • North Macedonia
  • Palestine Territories
  • Panama
  • Paraguay
  • Peru
  • Poland
  • Portugal
  • Qatar
  • Reunion ↑
  • Romania
  • Russia
  • Saint Martin/Sint Maarten
  • Serbia
  • Slovakia
  • Spain
  • St Vincent & The Grenadines
  • Sweden
  • Switzerland
  • Turkey
  • Ukraine
  • UAE
  • UK
  • Uruguay
  • USA – Alabama, Alaska, Arizona, Arkansas, California, Colorado, District of Colombia, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada , New Hampshire, New Jersey ↓, New Mexico, N Carolina ↓, Rhode Island ↓, N Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Vermont, Puerto Rico, S Dakota, Tennessee ↓, Texas, Utah, Virgin Islands, Washington, West Virginia, Wisconsin, Wyoming


>20-50 cases per 100,000 over 7 days

  • Armenia
  • Belize
  • Bolivia ↓
  • Cape Verde ↓
  • Costa Rica ↓
  • Curacao
  • Ecuador
  • Eswatini
  • Finland
  • French Guiana ↓
  • French Polynesia
  • Gabon
  • Guatemala
  • Guyana
  • Honduras ↓
  • Indonesia
  • Kazakhstan
  • Lesotho
  • Libya
  • Mexico
  • Montserrat
  • Norway
  • Oman
  • South Africa
  • Sri Lanka
  • Tunisia
  • USA – Hawaii
  • Zambia

We have recently reviewed how we classify countries, and we identify three distinct categories: Extreme, Severe and High. Extreme is >250 new cases per 100,000 over 7 days, Severe is >50-250 new cases per 100,000 over 7 days, and High is >20-50 new cases per 100,000 over 7 days. We include these categorisations in our communications to give an indication of country / regional risk rating and refine the categorisation using the following additional criteria:

  • Deaths per capita
  • Health care capacity
  • Prevalence of testing

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